EP1029358A1 - High voltage resistant edge structure for semiconductor elements - Google Patents
High voltage resistant edge structure for semiconductor elementsInfo
- Publication number
- EP1029358A1 EP1029358A1 EP98962198A EP98962198A EP1029358A1 EP 1029358 A1 EP1029358 A1 EP 1029358A1 EP 98962198 A EP98962198 A EP 98962198A EP 98962198 A EP98962198 A EP 98962198A EP 1029358 A1 EP1029358 A1 EP 1029358A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- edge structure
- voltage
- structure according
- edge
- semiconductor component
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
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Classifications
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D30/00—Field-effect transistors [FET]
- H10D30/60—Insulated-gate field-effect transistors [IGFET]
- H10D30/64—Double-diffused metal-oxide semiconductor [DMOS] FETs
- H10D30/66—Vertical DMOS [VDMOS] FETs
- H10D30/665—Vertical DMOS [VDMOS] FETs having edge termination structures
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
- H10D62/10—Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies
- H10D62/102—Constructional design considerations for preventing surface leakage or controlling electric field concentration
- H10D62/103—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices
- H10D62/105—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices by having particular doping profiles, shapes or arrangements of PN junctions; by having supplementary regions, e.g. junction termination extension [JTE]
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
- H10D62/10—Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies
- H10D62/102—Constructional design considerations for preventing surface leakage or controlling electric field concentration
- H10D62/103—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices
- H10D62/105—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices by having particular doping profiles, shapes or arrangements of PN junctions; by having supplementary regions, e.g. junction termination extension [JTE]
- H10D62/106—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices by having particular doping profiles, shapes or arrangements of PN junctions; by having supplementary regions, e.g. junction termination extension [JTE] having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
- H10D62/10—Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies
- H10D62/102—Constructional design considerations for preventing surface leakage or controlling electric field concentration
- H10D62/103—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices
- H10D62/105—Constructional design considerations for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse-biased devices by having particular doping profiles, shapes or arrangements of PN junctions; by having supplementary regions, e.g. junction termination extension [JTE]
- H10D62/109—Reduced surface field [RESURF] PN junction structures
- H10D62/111—Multiple RESURF structures, e.g. double RESURF or 3D-RESURF structures
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D12/00—Bipolar devices controlled by the field effect, e.g. insulated-gate bipolar transistors [IGBT]
- H10D12/411—Insulated-gate bipolar transistors [IGBT]
- H10D12/441—Vertical IGBTs
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D12/00—Bipolar devices controlled by the field effect, e.g. insulated-gate bipolar transistors [IGBT]
- H10D12/411—Insulated-gate bipolar transistors [IGBT]
- H10D12/441—Vertical IGBTs
- H10D12/461—Vertical IGBTs having non-planar surfaces, e.g. having trenches, recesses or pillars in the surfaces of the emitter, base or collector regions
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D30/00—Field-effect transistors [FET]
- H10D30/60—Insulated-gate field-effect transistors [IGFET]
- H10D30/64—Double-diffused metal-oxide semiconductor [DMOS] FETs
- H10D30/66—Vertical DMOS [VDMOS] FETs
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D64/00—Electrodes of devices having potential barriers
- H10D64/20—Electrodes characterised by their shapes, relative sizes or dispositions
- H10D64/23—Electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. sources, drains, anodes or cathodes
- H10D64/251—Source or drain electrodes for field-effect devices
- H10D64/256—Source or drain electrodes for field-effect devices for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies
Definitions
- the present invention relates to a high-voltage-resistant edge structure in the edge region of a semiconductor component according to the preamble of patent claim 1.
- a high-voltage-resistant edge structure is provided in the edge region of a semiconductor component with a semiconductor body, on the first surface of which at least one inner zone of the first conductivity type is adjacent, with at least one floating protection ring of the second conductivity type arranged in the inner zone and with at least one between the floating protection rings arranged intermediate ring zone of the first conduction type.
- voltage breakdowns preferably occur in their edge region outside the doping regions, since there the electric field strength is particularly large due to the curvature of the doping regions caused by the edge.
- doping regions arranged in a ring around the semiconductor components are therefore provided. These ring-shaped doping regions attenuate local field strength peaks in the edge region of the semiconductor component.
- guard rings are described, for example, in Canadian Patent No. 667,423.
- the floating guard rings described there must be dimensioned very wide towards the edge. This edge structure is therefore extremely space-consuming.
- edge structures of semiconductor components with so-called field plate rings are known from US Pat. No. 3,405,329. These field plate rings are designed such that a largely uniform voltage distribution is achieved along the surface of the semiconductor body of a semiconductor component. This prevents field strength peaks that promote the occurrence of a breakthrough. The implementation of these field plate rings in the edge region of the semiconductor component is also very space-consuming.
- No. 4,468,686 describes a high-voltage-resistant edge structure with field plate rings and ring-shaped doping regions arranged under the field plate rings. These ring-shaped doping regions essentially consist of a large number of MOS transistors connected in cascade. This edge structure also has an extremely area-consuming design in the edge region of the semiconductor component.
- the present invention is therefore based on the object of specifying a simple and space-saving design of a high-voltage-resistant edge structure for semiconductor components, which also ensures a reproducibly high breakdown voltage.
- a generic edge structure in which the conductivities and / or the geometries of the floating protective rings and / or the intermediate ring zones are set in such a way that their charge carriers completely clear out when the reverse voltage is applied.
- the edge structure according to the invention modulates the electrical field both on the surface and in the volume of the semiconductor body.
- the field strength maximum can be easily in the depth of the semiconductor body, ie in the area of the vertical pn Transition, postpone.
- a suitable design for an edge structure can always be specified over a wide concentration range of p- and n-doping, which permits a "soft" leakage of the electric field in the volume.
- the floating protective rings have the same width, the width of the intermediate ring zones which are arranged between the individual floating protective rings increasing toward the edge of the semiconductor component.
- the width of the floating protective rings decreases towards the edge of the semiconductor component, the intermediate ring zones between the individual floating protective rings each having the same width.
- the depth of the floating protective rings can be varied towards the edge of the semiconductor component. In particular, it is advantageous if the depth of the floating protective rings decreases towards the edge of the semiconductor component.
- the widths, distances and depths of the floating protective rings which can be defined by the lithography masks remain as design parameters for the edge structure according to the invention.
- an optimal edge structure can be designed with the simplest possible means for each semiconductor component and in particular for any range of the reverse voltage of a semiconductor component.
- the floating protective rings advantageously have a V-shaped trench or a U-shaped cross section in partial section.
- the V-trench cross section or the U-trench cross section can be produced in a simple manner by an isotropic or anisotropic etching process and a subsequent deposition process.
- a so-called space charge zone stopper is preferably also found in the edge region of the semiconductor component.
- a space charge zone stopper is to be understood as an electrode or a highly doped diffusion region in the outermost edge region, which limits the lateral extent of the space charge zone extending beyond the floating protective rings or the electrical field.
- the space charge zone stopper usually provides at least a multiple of the breakdown charge as a breakdown voltage.
- a heavily doped region of the same conductivity type as the epitaxial layer can be provided as the space charge zone stopper.
- the space charge zone stopper can be implemented as a so-called "damage-implanted” region (implantation region) or as a metal electrode which is short-circuited with the substrate material of the semiconductor body.
- the edge structure according to the invention is expediently provided with at least one field plate towards the edge, which ensures good electrostatic protection for the component against movable, parasitic charges in its housing. Furthermore, it has proven to be expedient that the cathode electrode adjacent to the edge structure, i. H. in the case of MOSFETs, their source electrode, vertically upwards towards the edge region, i.e. out of the semiconductor body to lead to allow the exit of the electric field from the semiconductor body.
- the corresponding design parameters are derived from the maximum permissible electrical field and essentially relate to a safe undershoot of a maximum interface charge in the region of the vertically extending pn junctions.
- this maximum interfacial charge is approximately 1.5 ⁇ 10 ⁇ 2 cm ⁇ 2.
- the edge structure according to the invention can be dimensioned up to 33% smaller in the lateral extent towards the edge of the semiconductor body.
- FIG. 1 shows a partial section of a high-voltage-resistant semiconductor component which is designed here as a D-MOSFET (or IGBT) and which has an edge structure according to the invention
- FIG. 2 shows a partial section of a further edge structure according to the invention
- FIG. 3 shows some partial sections in which different trench types are shown
- FIG. 4 shows some exemplary embodiments which are used to illustrate the generation of a selectively adjustable, homogeneous doping distribution in the edge region of a semiconductor component
- FIG. 5 shows some partial sections, on the basis of which various edge variations for setting a targeted, “soft” doping concentration in the edge region of a semiconductor component are shown.
- Figure 1 shows a partial section of a high voltage resistant
- the semiconductor component has a cell array ZF consisting of a plurality of individual components connected in parallel and each arranged in individual cells Z1..Z3, of which only the outermost three cells Z1..Z3 are shown.
- the cell field ZF is closed off by an edge structure provided in the edge region RB of the semiconductor component.
- the edge region RB here designates the region of the semiconductor component which is located outside the active cells Z1..Z3 of the cell field ZF.
- 1 denotes the semiconductor body of the semiconductor component.
- the semiconductor body 1 which consists, for example, of silicon substrate, has an n-doped inner zone 2 in the present exemplary embodiment which adjoins the first surface 3 of the semiconductor body 1 on the source side.
- the inner zone 2 has been applied to the semiconductor body 1 by an epitaxy process.
- this epitaxial layer is produced on the basis of several successive epitaxial steps, in each of which an epitaxial partial layer is applied to the layer below. This technology is known as construction technology.
- a drain zone 4 borders the inner zone 2 on the drain side.
- the drain zone 4 is typically heavily n-doped. However, if the semiconductor component is an IGBT, then the drain zone 4 is also referred to as an anode zone and is typically heavily p-doped (marked with brackets in FIG. 1). In this case, the interface 5 characterizes the pn junction between the drain zone 4 and the inner zone 2. In addition, the drain zone 4 borders on the second surface 6 of the semiconductor body 1 and is connected here over a large area to the drain electrode 7 and thus to the drain connection D.
- a multiplicity of base zones 8 are embedded in the inner zone 2 on the surface 3 on the source side.
- the base zones 8 have a conduction type opposite to the inner zone 2, i. H. in the case shown, they are p-doped.
- at least one heavily n-doped source zone 9 is embedded in each of the base zones 8.
- the base zones 8 and the source zones 9 embedded therein are trough-shaped and can be produced, for example, by ion implantation and / or by diffusion.
- the base zones 8 and / or the source zones 9 typically, but not necessarily, have the same cell design as the corresponding cells Z1..Z3 in which they are embedded.
- Such a cell design can consist, for example, of stripe-shaped, hexagonal, triangular, square, round, oval or similarly designed cells Z1..Z3.
- the semiconductor component in FIG. 1 is designed as a vertical D-MOSFET (or IGBT).
- the source zones 9 or the base zones 8 can also be arranged in a so-called trench or trench.
- the corresponding half The conductor component would then be a trench MOSFET or a trench IGBT.
- a V-shaped or trapezoidal cross section of the source zones 9 or the base zones 8 would also be conceivable.
- the source zones 9 and the base zones 8 are connected in a known manner to the source electrode 10 and thus to the source terminal S via contact holes 10 '. This shunt of the base zone 8 and the source zone 9 can prevent a parasitic bipolar transistor from being switched on there.
- a gate electrode 11 is provided on the first surface 3 and is insulated from the semiconductor body 1 via a thin gate oxide 12.
- the gate electrode 11 is connected to the gate connection G and can consist, for example, of highly doped polysilicon or of metal.
- a field oxide 13 is provided, which insulates the source electrode 10 from the gate electrode 11 and from the semiconductor body 1.
- the semiconductor component according to FIG. 1 has a space charge zone stop 14.
- This space charge zone stop 14 is at the outermost edge region RB of the semiconductor component, i. H. arranged directly in front of its edge.
- the space charge zone stopper 14 is designed in a known manner as a single-stage metal electrode 14 ′ rising up to the cell field ZF, which is contacted with a heavily n-doped diffusion region 14 ′′.
- the metal electrode 14 ' can also be designed as a polysilicon electrode or, depending on the application, can also be omitted.
- Step-shaped field plate rings 17 are usually provided in the edge region RB of a power semiconductor component. Such field plates 17 are typically designed in one or more stages, these field plates 17 being led away from the first surface 3 towards the edge hm. In execution Example of Figure 1, only a single-stage field plate 17 is shown.
- the gate electrodes 11 of the outermost cells ZI of the active cell field ZF simultaneously take over the function of the field plate 17.
- the source electrode 10 adjacent to the edge structure also likewise vertically upwards towards the edge region RB, ie. H. from the first
- protective rings 15 are provided in the edge area RB, i.e. H. outside the active cell field ZF.
- these floating protective rings 15 are column-shaped and extend from the first surface 3 of the semiconductor body 1 to deep into the inner zone 2.
- four of these floating protective rings 15 are provided.
- the floating protective rings 15 are spaced apart from one another, the area between the floating protective rings 15 defining an intermediate ring zone 16.
- This intermediate ring zone 16 typically, but not necessarily, has the same doping concentration as the background doping, that is to say the inner zone 2.
- the lateral and horizontal dimensions and geometries of the floating protective rings 15 and intermediate ring zones 16, as well as their doping concentration are not defined in more detail here. These are described in detail later with reference to FIGS. 3 to 5.
- the intermediate ring zones 16 are typically produced using the so-called "trench technology" (trench technology). In the present exemplary embodiment, the trenches of the intermediate ring zones 16 extend from the first surface 3 of the semiconductor body 1 deep into the inner zone 2.
- these trenches 16 run through the entire inner zone 2 and are connected to the drain zone 4. In principle, it is also conceivable that the trenches 16 pass through from the first surface 3 to the second surface 6 on the rear side of the wafer of the semiconductor body.
- FIG. 2 shows a further exemplary embodiment of an edge structure according to the invention on the basis of a partial section.
- the intermediate ring zones 16 are tapered in addition to the first surface 3 of the semiconductor body. It is also particularly advantageous if the source electrode 10 comprises the corresponding gate electrode 11 towards the edge region RB. I.e. the source electrode 10 protrudes toward the edge region RB beyond the corresponding outermost gate electrode 11 or the field plate 17 and is then pulled down again in the direction of the first surface 3 of the semiconductor body 1.
- the edge region RB in which the outermost gate electrode 11 or field plate 17 is virtually in a Faraday 'cage and is therefore located in an almost field-free space.
- the source electrode 10 in comparison to the conventional edge structure described in FIG. 1, in which the source electrode 10 is only drawn upwards towards the edge and towards ever thicker oxide layers of the field oxide 13, the source electrode 10 comprising the gate electrode 11 significantly reduces the achieved on the corresponding gate electrode 11 electric field.
- the above-described taper of the annular ring zones 16 to the first surface 3 toward the electric field strength can trode at the end of the metallization of the Sourceelek ⁇ 10 under the respective volume field strength lowered the advertising.
- the metal electrode 14 ′ of the space charge zone stopper 14 in the outermost region of the edge structure can additionally be drawn up to at least a second oxide level of the field oxide 13.
- the electrical field distribution in the open area OB of the edge structure that is to say in the area between the space charge zone stopper 14 and the field plate 17, is modified such that the field lines of the electric field over the entire open area OB are almost unchanged from the respective electrodes 14 '. 17 can emerge from the semiconductor body 1 on the first surface 3.
- the diffusion zone 14 ′′ under the metal electrode 14 ′ in the direction of the gate electrode 11 and the cell field ZF can be significantly reduced.
- the width of the above-mentioned open area OB between the space charge zone stopper 14 and the outermost cell ZI of the cell field ZF can thus be significantly reduced, which leads to a significant reduction in the area required for the edge structure according to the invention and thus the corresponding semiconductor component.
- trenches 18 are etched into the inner zone 2 of the semiconductor body 1.
- these trenches 18 are ideally column-shaped.
- the trenches 18 have a trench bottom 19 running approximately parallel to the first surface 3 and trench walls 20 which are ideally arranged at a right angle to the first surface 3.
- these trench walls 20 are angled and form at an angle of repose ⁇ relative to the horizontal thus a trench 18 tapering into the depth of the semiconductor body 1 with an approximately trapezoidal cross section (FIG. 3 (b)).
- FIG. 3 (b) trapezoidal cross section
- the trenches 18 to have a V-trench (FIG. 3 (c)) or U-trench (FIG. 3 (d)) cross section in partial section.
- Point, strip or lattice-shaped trenches 18 are etched into a comparatively highly doped base material of a first conduction type - for example the inner zone 2 (FIG. 4 (a)).
- the trenches 18 are filled epitaxially with material of the second conductivity type.
- the total charge is set so that there is an area-related net doping close to "0" and the area charge does not exceed the breakthrough charge in any spatial direction.
- a net doping close to "0" means here that the number of acceptors (holes) and the number of donors (electrons) are roughly balanced in the lateral projection.
- punctiform, strip-shaped or lattice-shaped trenches 18 are etched into a low-doped or undoped base material (FIG
- the trenches 18 are then coated with epitaxially deposited silicon, polycrystalline silicon or borophosphosilicate glass with a doping of the first conductivity type.
- the doping is driven into the surrounding base material, for example by a temperature process.
- the assignment is then etched out again. After that the trenches 18 by epitaxially deposited Sili ⁇ zium be replenished of the second conductivity type.
- a cavity 23 can also remain in the trench 18, provided that the trench walls 20 are covered by a passivation layer 21 and the cavity 2, 3 is closed at the top by a cover 22, for example made of borophosphosilicate glass (BPSG) ( Figure 4 (d)).
- BPSG borophosphosilicate glass
- FIG. 5 shows some partial sections, on the basis of which various edge variations for setting a targeted, “soft” doping concentration in the edge region of a semiconductor component are shown.
- the structures in accordance with FIGS. 1 and 2 have only been indicated schematically in FIG. 5, since the geometry, the dimensions and the spacing of the trenches 18 are particularly important here, in particular in the edge region RB of the semiconductor component.
- the trenches 18 can both from the first surface 3, ideally self-adjusting to the actual component process, that is, for example, adjusted to the polysilicon edge, or else etched from the rear or the second surface 6 after the semiconductor body 1 has been thinly ground. Both anisotropic etching and isotropic etching can be used. In principle, trenches 18 are also possible, which run through from the first surface 3 to the rear or the second surface 6 (FIG. 5 (a)). If these trenches 18 are doped sufficiently high, the use of the relatively expensive epitaxial disks can be avoided.
- the field strength distribution can be influenced favorably in the edge area RB.
- the depth t1> t2> t3 of the trenches 18 decreases continuously towards the edge. In this way, the location of the voltage breakdown can also be determined in the cell field ZF of the component.
- the doping assignment of the trenches in the radial or vertical direction (FIG. 5 (b)).
- the shape of the trenches 18 can be used deliberately for a vertical variation of the charge dose introduced.
- the slope angle ⁇ of the trench walls can also increase towards the edge.
- the so-called trench technique with etched trenches 18 has the advantage that smaller cell grids can be provided. These smaller cell grids can then have a higher doping, as a result of which the areal switch-on resistance RDS, ON is significantly reduced.
- each of the structures described in FIGS. 3 to 5 can of course be used alone or very advantageously in combination with one another in order to achieve the desired doping profile or the desired area-related doping distribution in the edge region RB.
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- Electrodes Of Semiconductors (AREA)
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- Semiconductor Integrated Circuits (AREA)
Abstract
Description
Beschreibungdescription
Hochspannungsfeste Randstruktur für HalbleiterbauelementeHigh-voltage-resistant edge structure for semiconductor components
Die vorliegende Erfindung betrifft eine hochspannungsfeste Randstruktur im Randbereich eines Halbleiterbauelementes gemäß dem Oberbegriff von Patentanspruch 1.The present invention relates to a high-voltage-resistant edge structure in the edge region of a semiconductor component according to the preamble of patent claim 1.
Demgemäß ist eine hochspannungsfeste Randstruktur im Randbe- reich eines Halbleiterbauelementes vorgesehen mit einem Halbleiterkörper, an dessen erste Oberfläche mindestens eine Innenzone vom ersten Leitungstyp angrenzt, mit mindestens einem in der Innenzone angeordneten floatenden Schutzring vom zweiten Leitungstyp und mit mindestens einer zwischen den floa- tenden Schutzringen angeordneten Zwischenringzone vom ersten Leitungstyp.Accordingly, a high-voltage-resistant edge structure is provided in the edge region of a semiconductor component with a semiconductor body, on the first surface of which at least one inner zone of the first conductivity type is adjacent, with at least one floating protection ring of the second conductivity type arranged in the inner zone and with at least one between the floating protection rings arranged intermediate ring zone of the first conduction type.
Bei Halbleiterbauelementen, insbesondere bei hochspannungsfesten Leistungshalbleiterbauelementen, treten Spannungsdurch- brüche bevorzugt in deren Randbereich außerhalb der Dotierungsgebiete auf, da dort die elektrische Feldstärke infolge der durch den Rand bedingten Krümmung der Dotierungsgebiete besonders groß ist. Um solche Spannungsdurchbrüche zu vermeiden, sind daher um die Halbleiterbauelemente herum ringförmig angeordnete Dotierungsgebiete vorgesehen. Durch diese ringförmigen Dotierungsgebiete werden lokale Feldstärkespitzen im Randbereich des Halbleiterbauelementes abgeschwächt.In the case of semiconductor components, in particular in the case of high-voltage-resistant power semiconductor components, voltage breakdowns preferably occur in their edge region outside the doping regions, since there the electric field strength is particularly large due to the curvature of the doping regions caused by the edge. In order to avoid such voltage breakdowns, doping regions arranged in a ring around the semiconductor components are therefore provided. These ring-shaped doping regions attenuate local field strength peaks in the edge region of the semiconductor component.
Solche Schutzringe sind beispielsweise in dem kanadischen Pa- tent Nr. 667,423 beschrieben. Da jedoch in jedem der Schutzringe die Feldstärke auf nahezu "0" reduziert werden muß, müssen die dort beschriebenen floatenden Schutzringe zum Rand hin sehr breit dimensioniert werden. Diese Randstruktur ist demnach äußerst flächenaufwendig.Such guard rings are described, for example, in Canadian Patent No. 667,423. However, since the field strength must be reduced to almost "0" in each of the guard rings, the floating guard rings described there must be dimensioned very wide towards the edge. This edge structure is therefore extremely space-consuming.
Ferner sind aus der US 3 , 405 , 329 Randstrukturen von Halbleiterbauelementen mit sogenannten Feldplattenringen bekannt . Diese Feldplattenringe sind derart ausgebildet, daß entlang der Oberfläche des Halbleiterkörpers eines Halbleiterbauelementes eine weitgehend gleichmäßige Spannungsverteilung erzielt wird. Dadurch werden Feldstärkespitzen, die das Auftre- ten eines Durchbruchs begünstigen, vermieden. Die Realisierung dieser Feldplattenringe ist im Randbereich des Halbleiterbauelementes ebenfalls sehr flächenaufwendig.Furthermore, edge structures of semiconductor components with so-called field plate rings are known from US Pat. No. 3,405,329. These field plate rings are designed such that a largely uniform voltage distribution is achieved along the surface of the semiconductor body of a semiconductor component. This prevents field strength peaks that promote the occurrence of a breakthrough. The implementation of these field plate rings in the edge region of the semiconductor component is also very space-consuming.
In der US 4,468,686 ist eine hochspannungsfeste Randstruktur mit Feldplattenringen und unter den Feldplattenringen angeordnete, ringförmige Dotierungsgebiete beschrieben. Diese ringförmigen Dotierungsgebiete bestehen im wesentlichen aus einer Vielzahl von in Kaskade geschalteten MOS-Transistoren. Diese Randstruktur weist ebenfalls ein äußerst flächenaufwen- diges Design im Randbereich des Halbleiterbauelements auf.No. 4,468,686 describes a high-voltage-resistant edge structure with field plate rings and ring-shaped doping regions arranged under the field plate rings. These ring-shaped doping regions essentially consist of a large number of MOS transistors connected in cascade. This edge structure also has an extremely area-consuming design in the edge region of the semiconductor component.
Ausgehend von diesem Stand der Technik liegt der vorliegenden Erfindung daher die Aufgabe zugrunde, eine einfache und platzsparende Ausführung einer hochspannungsfesten Randstruk- tur für Halbleiterbauelemente anzugeben, die darüber hinaus eine reproduzierbar hohe Durchbruchspannung sicherstellt.Starting from this prior art, the present invention is therefore based on the object of specifying a simple and space-saving design of a high-voltage-resistant edge structure for semiconductor components, which also ensures a reproducibly high breakdown voltage.
Erfindungsgemäß wird diese Aufgabe durch eine gattungsgemäße Randstruktur mit den Merkmalen des Patentanspruchs 1 gelöst.According to the invention, this object is achieved by a generic edge structure with the features of claim 1.
Demgemäß ist eine gattungsgemäße Randstruktur vorgesehen bei der die Leitfähigkeiten und/oder die Geometrien der floatenden Schutzringe und/oder der Zwischenringzonen derart eingestellt sind, daß sich deren Ladungsträger bei angelegter Sperrspannung vollständig ausräumen.Accordingly, a generic edge structure is provided in which the conductivities and / or the geometries of the floating protective rings and / or the intermediate ring zones are set in such a way that their charge carriers completely clear out when the reverse voltage is applied.
Durch die erfindungsgemäße Randstruktur wird eine Modulierung des elektrischen Feldes sowohl an der Oberfläche als auch im Volumen des Halbleiterkörpers erzielt. Bei geeigneter Dimen- sionierung der erfindungsgemäßen Randstruktur läßt sich das Feldstärkemaximum auf einfache Weise in die Tiefe des Halbleiterkörpers, d.h. in den Bereich des vertikalen pn- Überganges, verschieben. Dabei läßt sich über einen weiten Konzentrationsbereich von p- und n-Dotierung stets ein passendes Design für eine Randstruktur angeben, die ein "weiches" Auslaufen des elektrischen Feldes im Volumen er- laubt .The edge structure according to the invention modulates the electrical field both on the surface and in the volume of the semiconductor body. With a suitable dimensioning of the edge structure according to the invention, the field strength maximum can be easily in the depth of the semiconductor body, ie in the area of the vertical pn Transition, postpone. In this case, a suitable design for an edge structure can always be specified over a wide concentration range of p- and n-doping, which permits a "soft" leakage of the electric field in the volume.
In einer besonders vorteilhaften Ausführungsform der vorliegenden Erfindung weisen die floatenden Schutzringe dieselbe Breite auf, wobei die Breite der Zwischenringzonen, die zwi- sehen den einzelnen floatenden Schutzringen angeordnet sind, zum Rand des Halbleiterbauelementes hin zunimmt.In a particularly advantageous embodiment of the present invention, the floating protective rings have the same width, the width of the intermediate ring zones which are arranged between the individual floating protective rings increasing toward the edge of the semiconductor component.
In einer weiteren vorteilhaften Ausführungsform nimmt die Breite der floatenden Schutzringe zum Rand des Halbleiterbau- elementes hin ab, wobei die Zwischenringzonen zwischen den einzelnen floatenden Schutzringen jeweils die gleiche Breite aufweisen.In a further advantageous embodiment, the width of the floating protective rings decreases towards the edge of the semiconductor component, the intermediate ring zones between the individual floating protective rings each having the same width.
Darüber hinaus kann die Tiefe der floatenden Schutzringe zum Rand des Halbleiterbauelementes hin variiert werden. Insbesondere ist es vorteilhaft, wenn die Tiefe der floatenden Schutzringe zum Rand des Halbleiterbauelementes hin abnimmt.In addition, the depth of the floating protective rings can be varied towards the edge of the semiconductor component. In particular, it is advantageous if the depth of the floating protective rings decreases towards the edge of the semiconductor component.
Als Design Parameter bleiben demnach für die erfindungsgemäße Randstruktur die durch die Lithographiemasken definierbaren Breiten, Abstände und Tiefen der floatenden Schutzringe. Damit läßt sich für jedes Halbleiterbauelement und insbesondere für einen beliebigen Bereich der Sperrspannung eines Halbleiterbauelements eine optimale Randstruktur mit denkbar einfa- chen Mitteln konzipieren.Accordingly, the widths, distances and depths of the floating protective rings which can be defined by the lithography masks remain as design parameters for the edge structure according to the invention. In this way, an optimal edge structure can be designed with the simplest possible means for each semiconductor component and in particular for any range of the reverse voltage of a semiconductor component.
Vorteilhafterweise weisen die floatenden Schutzringe im Teilschnitt einen V-grabenförmigen oder einen U-grabenförmigen Querschnitt auf. Der V-grabenförmigen Querschnitt bzw. der U- grabenförmigen Querschnitt läßt sich auf einfache Weise durch einen isotropen bzw. anisotropen Atzprozeß und einen anschließenden Abscheideprozeß herstellen. Vorzugsweise findet sich im Randbereich des Halbleiterbauelementes auch ein sogenannter Raumladungszonenstopper. Unter einem Raumladungszonenstopper ist eine Elektrode oder ein hochdotiertes Diffusionsgebiet im äußersten Randbereich zu verstehen, die die laterale Ausdehnung der über die floatenden Schutzringe hinausgehenden Raumladungszone bzw. das elektrische Feld begrenzt. Der Raumladungszonenstopper stellt in der Regel als Durchbruchspannung zumindest ein Vielfaches der Durchbruchsladung bereit. Als Raumladungszonenstopper kann ein stark dotiertes Gebiet vom selben Leitungstyp wie die Epitaxieschicht vorgesehen sein. Je nach Anforderung wäre es auch denkbar, den Raumladungszonenstopper als sogenanntes "damage-implantiertes" Gebiet (Implantationsgebiet) bzw. als Metallelektrode, die mit dem Substratmaterial des Halbleiterkörpers kurzgeschlossen ist, zu realisieren.The floating protective rings advantageously have a V-shaped trench or a U-shaped cross section in partial section. The V-trench cross section or the U-trench cross section can be produced in a simple manner by an isotropic or anisotropic etching process and a subsequent deposition process. A so-called space charge zone stopper is preferably also found in the edge region of the semiconductor component. A space charge zone stopper is to be understood as an electrode or a highly doped diffusion region in the outermost edge region, which limits the lateral extent of the space charge zone extending beyond the floating protective rings or the electrical field. The space charge zone stopper usually provides at least a multiple of the breakdown charge as a breakdown voltage. A heavily doped region of the same conductivity type as the epitaxial layer can be provided as the space charge zone stopper. Depending on the requirements, it would also be conceivable to implement the space charge zone stopper as a so-called "damage-implanted" region (implantation region) or as a metal electrode which is short-circuited with the substrate material of the semiconductor body.
Zweckmäßigerweise wird die erfindungsgemäße Randstruktur zum Rand hin mit mindestens einer Feldplatte versehen, die für das Bauelement einen guten elektrostatischen Schutz gegenüber beweglichen, parasitären Ladungen in dessen Gehäuse gewährleistet. Ferner hat es sich als zweckmäßig erwiesen, die der Randstruktur benachbarte Kathoden-Elektrode, d. h. bei MOS- FETs deren Source-Elektrode, zum Randbereich hin vertikal nach oben, d.h. aus dem Halbleiterkörper heraus, zu führen, um den Austritt des elektrischen Feldes aus dem Halbleiterkörper zu ermöglichen.The edge structure according to the invention is expediently provided with at least one field plate towards the edge, which ensures good electrostatic protection for the component against movable, parasitic charges in its housing. Furthermore, it has proven to be expedient that the cathode electrode adjacent to the edge structure, i. H. in the case of MOSFETs, their source electrode, vertically upwards towards the edge region, i.e. out of the semiconductor body to lead to allow the exit of the electric field from the semiconductor body.
Für die gesamte Randstruktur leiten sich die entsprechenden Designparameter aus dem maximal zulässigen elektrischen Feld ab und beziehen sich im wesentlichen auf eine sichere Unterschreitung einer maximalen Grenzflächenladung im Bereich der vertikal verlaufenden pn-Übergänge . Bei Silizium beträgt diese maximale Grenzflächenladung etwa 1,5 x 10^2 cm~2. Damit ergibt sich aus einem gegebenen Dotierungsprofil des Halbleiterkörpers im Randbereich ein sehr einfach zu handhabendes Layout. Die Verlagerung des Feldstärkemaximums in den Bereich der Übergänge zwischen den einzelnen floatenden Schutzringen und dazwischen angeordneten Zwischenringzonen wird durch einen flächenbezogenen Nettoüberschuß an Akzeptoratomen erzielt. Das bedeutet, daß die flächenbezogene Summe der einge- brachten Dotierstoffe in den floatenden Schutzringen die Summe der Dotierung in den dazwischen angeordneten Zwischenringzonen übersteigen muß.For the entire edge structure, the corresponding design parameters are derived from the maximum permissible electrical field and essentially relate to a safe undershoot of a maximum interface charge in the region of the vertically extending pn junctions. In the case of silicon, this maximum interfacial charge is approximately 1.5 × 10 ^ 2 cm ~ 2. This results in a layout that is very easy to use from a given doping profile of the semiconductor body in the edge region. The shift of the field strength maximum into the area the transitions between the individual floating guard rings and intermediate ring zones arranged between them are achieved by a surface-related net excess of acceptor atoms. This means that the area-related sum of the dopants introduced in the floating protective rings must exceed the sum of the doping in the intermediate ring zones arranged between them.
Gegenüber einer konventionellen Randstruktur kann die erfin- dungsgemäße Randstruktur in der lateralen Ausdehnung zum Rand des Halbleiterkörpers hin um bis zu 33% kleiner dimensioniert sein.Compared to a conventional edge structure, the edge structure according to the invention can be dimensioned up to 33% smaller in the lateral extent towards the edge of the semiconductor body.
Weitere vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung sind den jeweiligen Unteransprüchen zu entnehmen.Further advantageous refinements and developments of the invention can be found in the respective subclaims.
Die Erfindung wird nachfolgend anhand der in den Figuren der Zeichnung angegebenen Ausführungsbeispiele näher beschrieben. Es zeigt dabei:The invention is described below with reference to the embodiments shown in the figures of the drawing. It shows:
Figur 1 einen Teilschnitt eines hochspannungsfesten Halbleiterbauelementes, das hier als D-MOSFET (bzw. IGBT) ausgebildet ist und das eine erfindungsgemäße Randstruktur aufweist;FIG. 1 shows a partial section of a high-voltage-resistant semiconductor component which is designed here as a D-MOSFET (or IGBT) and which has an edge structure according to the invention;
Figur 2 einen Teilschnitt einer weiteren erfindungsgemäßen Randstruktur;FIG. 2 shows a partial section of a further edge structure according to the invention;
Figur 3 einige Teilschnitte, in denen verschiedene Trench-Ty- pen dargestellt sind;FIG. 3 shows some partial sections in which different trench types are shown;
Figur 4 einige Ausführungsbeispiele, anhand derer die Erzeugung einer gezielt einstellbaren, homogenen Dotierungsverteilung im Randbereich eines Halbleiterbau- elementes veranschaulicht wird; Figur 5 einige Teilschnitte, anhand derer verschiedene Randvariationen zur Einstellung einer gezielten, "weich" auslaufenden Dotierungskonzentration im Randbereich eines Halbleiterbauelementes dargestellt werden.FIG. 4 shows some exemplary embodiments which are used to illustrate the generation of a selectively adjustable, homogeneous doping distribution in the edge region of a semiconductor component; FIG. 5 shows some partial sections, on the basis of which various edge variations for setting a targeted, “soft” doping concentration in the edge region of a semiconductor component are shown.
In allen Figuren der Zeichnung sind gleiche oder funktionsgleiche Elemente, sofern nicht anders angegeben, mit gleichen Bezugszeichen versehen.In all figures of the drawing, identical or functionally identical elements are provided with the same reference symbols, unless stated otherwise.
Figur 1 zeigt einen Teilschnitt eines hochspannungsfestenFigure 1 shows a partial section of a high voltage resistant
(Leistungs-) Halbleiterbauelementes, das eine erfindungsgemäße Randstruktur aufweist.(Power) semiconductor component which has an edge structure according to the invention.
Das Halbleiterbauelement weist ein Zellenfeld ZF bestehend aus einer Vielzahl von parallel geschalteten und jeweils in einzelnen Zellen Z1..Z3, von denen lediglich ausschnittsweise die äußersten drei Zellen Z1..Z3 dargestellt sind, angeordneten Einzelbauelementen auf. Das Zellenfeld ZF wird durch eine im Randbereich RB des Halbleiterbauelementes vorgesehene Randstruktur abgeschlossen. Der Randbereich RB bezeichnet hier den Bereich des Halbleiterbauelementes, der sich außerhalb dessen aktiven Zellen Z1..Z3 des Zellenfeldes ZF befindet.The semiconductor component has a cell array ZF consisting of a plurality of individual components connected in parallel and each arranged in individual cells Z1..Z3, of which only the outermost three cells Z1..Z3 are shown. The cell field ZF is closed off by an edge structure provided in the edge region RB of the semiconductor component. The edge region RB here designates the region of the semiconductor component which is located outside the active cells Z1..Z3 of the cell field ZF.
In Figur 1 ist mit 1 der Halbleiterkörper des Halbleiterbauelementes bezeichnet. Der Halbleiterkörper 1 der beispielsweise aus Siliziumsubstrat besteht, weist eine im vorliegenden Ausführungsbeispiel n-dotierte Innenzone 2 auf, die sour- ceseitig an die erste Oberfläche 3 des Halbleiterkörpers 1 angrenzt. Typischerweise ist die Innenzone 2 durch einen Epitaxieprozeß auf den Halbleiterkörper 1 aufgebracht worden. Insbesondere bei hochspannungsfesten Leistungshalbleiterbauelementen mit sehr hoher Sperrspannung wird diese Epitaxieschicht anhand von mehreren aufeinanderfolgenden Epitaxie- schritten, bei denen jeweils eine Epitaxieteilschicht auf die darunterliegende Schicht aufgebracht wird, erzeugt. Diese Technologie ist als Aufbautechnik bekannt. Drainseitig grenzt eine Drainzone 4 an die Innenzone 2 an. Ist das Halbleiterbauelement beispielsweise als MOSFET ausgebildet, dann ist die Drainzone 4 typischerweise stark n- dotiert. Ist das Halbleiterbauelement jedoch ein IGBT, dann wird die Drainzone 4 auch als Anodenzone bezeichnet und ist typischerweise stark p-dotiert (in Figur 1 mit Klammern gekennzeichnet) . In diesem Fall charakterisiert die Grenzfläche 5 den pn-Übergang zwischen Drainzone 4 und Innenzone 2. Darüber hinaus grenzt die Drainzone 4 an die zweite Oberfläche 6 des Halbleiterkörpers 1 an und ist hier großflächig an die Draineleketrode 7 und somit an den Drainanschluß D angeschlossen.In FIG. 1, 1 denotes the semiconductor body of the semiconductor component. The semiconductor body 1, which consists, for example, of silicon substrate, has an n-doped inner zone 2 in the present exemplary embodiment which adjoins the first surface 3 of the semiconductor body 1 on the source side. Typically, the inner zone 2 has been applied to the semiconductor body 1 by an epitaxy process. In particular in the case of high-voltage-resistant power semiconductor components with a very high reverse voltage, this epitaxial layer is produced on the basis of several successive epitaxial steps, in each of which an epitaxial partial layer is applied to the layer below. This technology is known as construction technology. A drain zone 4 borders the inner zone 2 on the drain side. If the semiconductor component is designed, for example, as a MOSFET, then the drain zone 4 is typically heavily n-doped. However, if the semiconductor component is an IGBT, then the drain zone 4 is also referred to as an anode zone and is typically heavily p-doped (marked with brackets in FIG. 1). In this case, the interface 5 characterizes the pn junction between the drain zone 4 and the inner zone 2. In addition, the drain zone 4 borders on the second surface 6 of the semiconductor body 1 and is connected here over a large area to the drain electrode 7 and thus to the drain connection D.
An der sourceseitigen Oberfläche 3 sind eine Vielzahl von Basiszonen 8 in die Innenzone 2 eingebettet. Die Basiszonen 8 weisen einen gegenüber der Innenzone 2 entgegengesetzten Leitungstyp auf, d. h. sie sind im gezeigten Fall p-dotiert. Im vorliegenden Ausführungsbeispiel ist in jeder der Basiszonen 8 jeweils mindestens eine stark n-dotierte Sourcezone 9 eingebettet. Im vorliegenden Ausführungsbeispiel sind die Basiszonen 8 und die darin eingebetteten Sourcezonen 9 wannenför- mig ausgebildet und können beispielsweise durch Ionenimplantation und/oder durch Diffusion erzeugt werden.A multiplicity of base zones 8 are embedded in the inner zone 2 on the surface 3 on the source side. The base zones 8 have a conduction type opposite to the inner zone 2, i. H. in the case shown, they are p-doped. In the present exemplary embodiment, at least one heavily n-doped source zone 9 is embedded in each of the base zones 8. In the present exemplary embodiment, the base zones 8 and the source zones 9 embedded therein are trough-shaped and can be produced, for example, by ion implantation and / or by diffusion.
Die Basiszonen 8 und/oder die Sourcezonen 9 weisen typischerweise, jedoch nicht notwendigerweise, dasselbe Zelldesign wie die entsprechenden Zellen Z1..Z3, in denen sie eingebettet sind, auf. Ein solches Zelldesign kann beispielsweise aus streifenförmigen, hexagonalen, dreieckigen, viereckigen, runden, ovalen oder ähnlich ausgebildeten Zellen Z1..Z3 bestehen.The base zones 8 and / or the source zones 9 typically, but not necessarily, have the same cell design as the corresponding cells Z1..Z3 in which they are embedded. Such a cell design can consist, for example, of stripe-shaped, hexagonal, triangular, square, round, oval or similarly designed cells Z1..Z3.
Das Halbleiterbauelement in Figur 1 ist als vertikaler D- MOSFET (bzw. IGBT) ausgebildet. Selbstverständlich können die Sourcezonen 9 bzw. die Basiszonen 8 auch in einem sogenannten Trench bzw. Graben angeordnet sein. Das entsprechende Halb- leiterbauelement wäre dann ein Trench-MOSFET bzw. ein Trench- IGBT . Denkbar wäre jedoch auch ein V-formiger oder trapezförmiger Querschnitt der Sourcezonen 9 bzw. der Basiszonen 8.The semiconductor component in FIG. 1 is designed as a vertical D-MOSFET (or IGBT). Of course, the source zones 9 or the base zones 8 can also be arranged in a so-called trench or trench. The corresponding half The conductor component would then be a trench MOSFET or a trench IGBT. However, a V-shaped or trapezoidal cross section of the source zones 9 or the base zones 8 would also be conceivable.
In Figur 1 sind die Sourcezonen 9 und die Basiszonen 8 in bekannter Weise über Kontaktlocher 10' mit der Sourceelektrode 10 und damit mit dem Sourceanschluß S verbunden. Durch diesen Nebenschluß der Basiszone 8 und der Sourcezone 9 kann vermieden werden, daß dort ein parasitärer Bipolartransistor einge- schaltet wird.In FIG. 1, the source zones 9 and the base zones 8 are connected in a known manner to the source electrode 10 and thus to the source terminal S via contact holes 10 '. This shunt of the base zone 8 and the source zone 9 can prevent a parasitic bipolar transistor from being switched on there.
Darüber hinaus ist an der ersten Oberflache 3 eine Gateelektrode 11 vorgesehen, die über ein dünnes Gateoxid 12 gegen den Halbleiterkorper 1 isoliert ist. Die Gateelektrode 11 ist mit dem Gateanschluß G verbunden und kann beispielsweise aus hochdotiertem Polysilizium bzw. aus Metall bestehen. Ferner ist ein Feldoxid 13 vorgesehen, welches die Sourceelektrode 10 gegen die Gateelektrode 11 sowie gegen den Halbleiterkorper 1 isoliert.In addition, a gate electrode 11 is provided on the first surface 3 and is insulated from the semiconductor body 1 via a thin gate oxide 12. The gate electrode 11 is connected to the gate connection G and can consist, for example, of highly doped polysilicon or of metal. Furthermore, a field oxide 13 is provided, which insulates the source electrode 10 from the gate electrode 11 and from the semiconductor body 1.
Schließlich weist das Halbleiterbauelement gemäß Figur 1 einen Raumladungszonenstopper 14 auf. Dieser Raumladungszonenstopper 14 ist am äußersten Randbereich RB des Halbleiterbauelementes, d. h. unmittelbar vor dessen Sagekante, angeord- net. Im vorliegenden Ausfuhrungsbeispiel ist der Raumladungszonenstopper 14 in bekannter Weise als eine zum Zellenfeld ZF hin aufsteigende, einstufige Metallelektrode 14', die mit einem stark n-dotierten Diffusionsgebiet 14'' kontaktiert ist, ausgebildet. Die Metallelektrode 14' kann jedoch auch als Po- lysiliziumelektrode ausgebildet sein oder je nach Applikation auch weggelassen werden.Finally, the semiconductor component according to FIG. 1 has a space charge zone stop 14. This space charge zone stop 14 is at the outermost edge region RB of the semiconductor component, i. H. arranged directly in front of its edge. In the present exemplary embodiment, the space charge zone stopper 14 is designed in a known manner as a single-stage metal electrode 14 ′ rising up to the cell field ZF, which is contacted with a heavily n-doped diffusion region 14 ″. However, the metal electrode 14 'can also be designed as a polysilicon electrode or, depending on the application, can also be omitted.
Üblicherweise sind im Randbereich RB eines Leistungshalblei- terbauelementes stufenförmige Feldplattenringe 17 vorgesehen. Solche Feldplatten 17 sind typischerweise einstufig oder mehrstufig ausgebildet, wobei diese Feldplatten 17 zum Rand hm von der ersten Oberflache 3 weggeführt werden. Im Ausfuh- rungsbeispiel gemäß Figur 1 ist lediglich eine einstufig ausgebildete Feldplatte 17 dargestellt.Step-shaped field plate rings 17 are usually provided in the edge region RB of a power semiconductor component. Such field plates 17 are typically designed in one or more stages, these field plates 17 being led away from the first surface 3 towards the edge hm. In execution Example of Figure 1, only a single-stage field plate 17 is shown.
Aus Gründen der Flächenoptimierung hat es sich weiters als sehr vorteilhaft erwiesen, daß die Gateelektroden 11 der jeweils äußersten Zellen ZI des aktiven Zellenfeldes ZF gleichzeitig die Funktion der Feldplatte 17 übernimmt. Ferner hat es sich als vorteilhaft erwiesen, daß die der Randstruktur benachbarte Sourceelektrode 10 zum Randbereich RB hin eben- falls ebenfalls vertikal nach oben, d. h. von der erstenFor reasons of surface optimization, it has furthermore proven to be very advantageous that the gate electrodes 11 of the outermost cells ZI of the active cell field ZF simultaneously take over the function of the field plate 17. Furthermore, it has proven to be advantageous that the source electrode 10 adjacent to the edge structure also likewise vertically upwards towards the edge region RB, ie. H. from the first
Oberfläche 3 des Halbleiterkörpers 1 herausgeführt wird. Dies ermöglicht den Austritt des elektrischen Feldes aus dem Halbleiterkörper 1.Surface 3 of the semiconductor body 1 is led out. This enables the electrical field to emerge from the semiconductor body 1.
Erfindungsgemäß sind im Randbereich RB, d. h. außerhalb des aktiven Zellenfeldes ZF, Schutzringe 15 vorgesehen. Diese Schutzringe 15, die im vorliegenden Ausführungsbeispiel schwach p-dotiert ausgebildet sind, sind "floatend", d. h. sie weisen ein Undefiniertes Potential auf. In dem Teil- schnitt in Figur 1 sind diese floatenden Schutzringe 15 säulenförmig ausgebildet und reichen von der ersten Oberfläche 3 des Halbleiterkörpers 1 bis tief in der Innenzone 2 hinein. Im Ausführungsbeispiel gemäß der Figur 1 sind vier dieser floatenden Schutzringe 15 vorgesehen.According to the invention in the edge area RB, i.e. H. outside the active cell field ZF, protective rings 15 are provided. These protective rings 15, which are weakly p-doped in the present exemplary embodiment, are "floating", i. H. they have an undefined potential. In the partial section in FIG. 1, these floating protective rings 15 are column-shaped and extend from the first surface 3 of the semiconductor body 1 to deep into the inner zone 2. In the exemplary embodiment according to FIG. 1, four of these floating protective rings 15 are provided.
Die floatenden Ξchutzringe 15 sind voneinander beabstandet, wobei der Bereich zwischen den floatenden Schutzringen 15 eine Zwischenringzone 16 definiert. Diese Zwischenringzone 16 weist typischerweise, jedoch nicht notwendigerweise, dieselbe Dotierungskonzentration wie die Untergrunddotierung, daß heißt also die Innenzone 2, auf. Die lateralen und horizontalen Abmessungen und Geometrien der floatenden Schutzringe 15 und Zwischenringzonen, 16 sowie deren Dotierungskonzentration seien an dieser Stelle nicht näher definiert. Diese werden später anhand der Figuren 3 bis 5 genau beschrieben. Die Zwischenringzonen 16 sind typischerweise in der sogenannten "Trench-Technologie" (Grabentechnologie) hergestellt. Im vorliegenden Ausführungsbeispiel reichen die Gräben der Zwischenringzonen 16 von der ersten Oberfläche 3 des Halbleiter- körpers 1 tief in die Innenzone 2 hinein. Es wäre selbstverständlich auch denkbar, daß diese Gräben 16 durch die gesamte Innenzone 2 verlaufen und an die Drainzone 4 angeschlossen sind. Prinzipiell ist es auch denkbar, daß die Gräben 16 von der ersten Oberfläche 3 bis zur zweiten Oberfläche 6 an der Scheibenrückseite des Halbleiterkörpers durchgehen. DieserThe floating protective rings 15 are spaced apart from one another, the area between the floating protective rings 15 defining an intermediate ring zone 16. This intermediate ring zone 16 typically, but not necessarily, has the same doping concentration as the background doping, that is to say the inner zone 2. The lateral and horizontal dimensions and geometries of the floating protective rings 15 and intermediate ring zones 16, as well as their doping concentration are not defined in more detail here. These are described in detail later with reference to FIGS. 3 to 5. The intermediate ring zones 16 are typically produced using the so-called "trench technology" (trench technology). In the present exemplary embodiment, the trenches of the intermediate ring zones 16 extend from the first surface 3 of the semiconductor body 1 deep into the inner zone 2. It would of course also be conceivable that these trenches 16 run through the entire inner zone 2 and are connected to the drain zone 4. In principle, it is also conceivable that the trenches 16 pass through from the first surface 3 to the second surface 6 on the rear side of the wafer of the semiconductor body. This
Sachverhalt wird später anhand der Figur 5 noch eingehend beschrieben.The situation will be described in detail later with reference to FIG. 5.
Figur 2 zeigt anhand eines Teilschnittes ein weiteres Ausfüh- rungsbeispiel einer erfindungsgemäßen Randstruktur.FIG. 2 shows a further exemplary embodiment of an edge structure according to the invention on the basis of a partial section.
In Figur 2 sind die Zwischenringzonen 16 zusätzlich zur ersten Oberfläche 3 des Halbleiterkörpers hin verjüngt. Besonders vorteilhaft ist es darüberhinaus, wenn die Sourceelek- trode 10 zum Randbereich RB hin die entsprechende Gateelektrode 11 umfaßt. D. h. die Sourceelektrode 10 ragt zum Randbereich RB hin über die entsprechende, äußerste Gateelektrode 11 bzw. die Feldplatte 17 hinaus und wird dann wieder in Richtung zur ersten Oberfläche 3 des Halbleiterkörpers 1 her- untergezogen.In FIG. 2, the intermediate ring zones 16 are tapered in addition to the first surface 3 of the semiconductor body. It is also particularly advantageous if the source electrode 10 comprises the corresponding gate electrode 11 towards the edge region RB. I.e. the source electrode 10 protrudes toward the edge region RB beyond the corresponding outermost gate electrode 11 or the field plate 17 and is then pulled down again in the direction of the first surface 3 of the semiconductor body 1.
Auf diese Weise entsteht im Randbereich RB eine Struktur, bei der die äußerste Gateelektrode 11 bzw. Feldplatte 17 sich quasi in einem Faraday' sehen Käfig und somit in einem nahezu feldfreien Raum befindet. Im Vergleich zu der in Figur 1 beschriebenen konventionellen Randstruktur, bei der die Source- Elektrode 10 lediglich zum Rand hin nach oben, zu immer dik- keren Oxidschichten des Feldoxids 13 gezogen wird, wird durch die die Gateelektrode 11 umfassende Sourceelektrode 10 eine deutliche Reduktion des auf die entsprechende Gateelektrode 11 gerichteten elektrischen Feldes erzielt. Durch die oben beschriebene Verjüngung der ringförmigen Zwischenringzonen 16 zur ersten Oberfläche 3 hin kann die elektrische Feldstärke am Ende der Metallisierung der Sourceelek¬ trode 10 unter die jeweilige Volumenfeldstärke abgesenkt wer- den. In einer völligen Umkehrung des bisherigen Designs kann somit die Metallelektrode 14' des Raumladungszonenstopper 14 im äußersten Bereich der Randstruktur zusätzlich auf mindestens eine zweite Oxidstufe des Feldoxids 13 heraufgezogen werden. Auf diese Weise wird die elektrische Feldverteilung im offenen Bereich OB der Randstruktur, daß heißt also im Bereich zischen Raumladungszonenstopper 14 und Feldplatte 17, derart modifiziert, daß die Feldlinien des elektrischen Feldes über den gesamten offenen Bereich OB nahezu unverändert von den jeweiligen Elektroden 14', 17 an der ersten Oberflä- ehe 3 aus dem Halbleiterkörper 1 heraustreten können. Auf diese Weise läßt sich die Diffusionszone 14'' unter der Metallelektrode 14' in Richtung Gateelektrode 11 und Zellenfeld ZF deutlich reduzieren. Die Breite des oben genannten offenen Bereiches OB zwischen dem Raumladungszonenstopper 14 und der äußersten Zelle ZI des Zellenfeldes ZF kann damit signifikant verringert werden, was zu einer deutlichen Reduzierung des Flächenaufwandes der erfindungsgemäßen Randstruktur und damit des entsprechenden Halbleiterbauelementes führt.In this way, a structure is created in the edge region RB, in which the outermost gate electrode 11 or field plate 17 is virtually in a Faraday 'cage and is therefore located in an almost field-free space. In comparison to the conventional edge structure described in FIG. 1, in which the source electrode 10 is only drawn upwards towards the edge and towards ever thicker oxide layers of the field oxide 13, the source electrode 10 comprising the gate electrode 11 significantly reduces the achieved on the corresponding gate electrode 11 electric field. The above-described taper of the annular ring zones 16 to the first surface 3 toward the electric field strength can trode at the end of the metallization of the Sourceelek ¬ 10 under the respective volume field strength lowered the advertising. In a complete reversal of the previous design, the metal electrode 14 ′ of the space charge zone stopper 14 in the outermost region of the edge structure can additionally be drawn up to at least a second oxide level of the field oxide 13. In this way, the electrical field distribution in the open area OB of the edge structure, that is to say in the area between the space charge zone stopper 14 and the field plate 17, is modified such that the field lines of the electric field over the entire open area OB are almost unchanged from the respective electrodes 14 '. 17 can emerge from the semiconductor body 1 on the first surface 3. In this way, the diffusion zone 14 ″ under the metal electrode 14 ′ in the direction of the gate electrode 11 and the cell field ZF can be significantly reduced. The width of the above-mentioned open area OB between the space charge zone stopper 14 and the outermost cell ZI of the cell field ZF can thus be significantly reduced, which leads to a significant reduction in the area required for the edge structure according to the invention and thus the corresponding semiconductor component.
In Figur 3 sind anhand von Teilschnitten einige Trechntypen dargestellt .In FIG. 3, some types of calculations are shown using partial sections.
Zur Herstellung der Zwischenringzonen 16 mittels der Trechn- technologie werden Gräben 18 in die Innenzone 2 des Halblei- terkörpers 1 geätzt. In Figur 1 sowie in Figur 3(a) sind diese Gräben 18 idealerweise säulenartig ausgebildet. Im vorliegenden Ausführungsbeispiel weisen die Gräben 18 einen etwa parallel zur ersten Oberfläche 3 verlaufenen Grabenboden 19 sowie Grabenwände 20 auf, die idealerweise in einem rechten Winkel zur ersten Oberfläche 3 angeordnet sind. Typischerweise sind jedoch eben diese Grabenwände 20 in einem Böschungswinkel α gegenüber der Waagerechten abgewinkelt und bilden somit ein sich in die Tiefe des Halbleiterkörpers 1 hin verjüngenden Graben 18 mit annähernd trapetzförmigen Querschnitt (Figur 3 (b) ) . Dies ist jedoch nicht zwingend notwendig. Es wäre selbstverständlich auch denkbar, daß die Gräben 18 im Teilschnitt einen V-grabenförmigen (Figur 3(c)) oder U- grabenförmigen (Figur 3 (d) ) Querschnitt aufweisen.To produce the intermediate ring zones 16 by means of the computing technology, trenches 18 are etched into the inner zone 2 of the semiconductor body 1. In FIG. 1 and in FIG. 3 (a), these trenches 18 are ideally column-shaped. In the present exemplary embodiment, the trenches 18 have a trench bottom 19 running approximately parallel to the first surface 3 and trench walls 20 which are ideally arranged at a right angle to the first surface 3. Typically, however, these trench walls 20 are angled and form at an angle of repose α relative to the horizontal thus a trench 18 tapering into the depth of the semiconductor body 1 with an approximately trapezoidal cross section (FIG. 3 (b)). However, this is not absolutely necessary. It would of course also be conceivable for the trenches 18 to have a V-trench (FIG. 3 (c)) or U-trench (FIG. 3 (d)) cross section in partial section.
Nachfolgend werden anhand von Figur 4 einige bevorzugte Verfahren zur Herstellung einer gezielt einstellbaren, homogenen Dotierungsverteilung im Randbereich eines Halbleiterbauelementes und damit einer erfindungsgemäßen Randstruktur beschrieben. In allen Teilfiguren 4 (a) - (d) ist der besseren Übersicht heit halber lediglich ein einzelner Graben 18 dargestellt :Some preferred methods for producing a selectively adjustable, homogeneous doping distribution in the edge region of a semiconductor component and thus an edge structure according to the invention are described below with reference to FIG. 4. For the sake of clarity, only a single trench 18 is shown in all sub-figures 4 (a) - (d):
Es werden punkt-, streifen- oder gitterförmige Gräben 18 in ein vergleichsweise hochdotiertes Grundmaterial eines ersten Leitungstyps - beispielsweise die Innenzone 2 - geätzt (Figur 4(a)). Die Gräben 18 werden epitaktisch mit Material des zweiten Leitungstyps aufgefüllt. Dabei wird die Gesamtladung so eingestellt, daß sich eine flächenbezogene Nettodotierung nahe "0" ergibt und die Flächenladung in keiner Raumrichtung die Durchbruchsladung übersteigt. Eine Nettodotierung nahe "0" bedeutet hier, daß sich die Zahl der Akzeptoren (Löcher) und die Zahl der Donatoren (Elektronen) in der lateralen Projektion etwa die Waage halten.Point, strip or lattice-shaped trenches 18 are etched into a comparatively highly doped base material of a first conduction type - for example the inner zone 2 (FIG. 4 (a)). The trenches 18 are filled epitaxially with material of the second conductivity type. The total charge is set so that there is an area-related net doping close to "0" and the area charge does not exceed the breakthrough charge in any spatial direction. A net doping close to "0" means here that the number of acceptors (holes) and the number of donors (electrons) are roughly balanced in the lateral projection.
In einer anderen Ausführung der vorliegenden Erfindung werden punkt-, streifen- oder gitterförmige Gräben 18 in ein nied- rigdotiertes oder undotiertes Grundmaterial geätzt (FigurIn another embodiment of the present invention, punctiform, strip-shaped or lattice-shaped trenches 18 are etched into a low-doped or undoped base material (FIG
4 (b) ) . Danach werden die Gräben 18 mittels epitaktisch abgeschiedenem Silizium, polykristallinem Silizium oder Borphosphorsilikatglas mit einer Dotierung vom ersten Leitungstyp belegt. Die Dotierung wird in das umgebende Grundmaterial, beispielsweise durch einen Temperaturprozeß, eingetrieben. Die Belegung wird anschließend wieder herausgeätzt. Danach werden die Gräben 18 mittels epitaktisch abgeschiedenem Sili¬ zium vom zweiten Leitungstyp wieder aufgefüllt.4 (b)). The trenches 18 are then coated with epitaxially deposited silicon, polycrystalline silicon or borophosphosilicate glass with a doping of the first conductivity type. The doping is driven into the surrounding base material, for example by a temperature process. The assignment is then etched out again. After that the trenches 18 by epitaxially deposited Sili ¬ zium be replenished of the second conductivity type.
In einer vorteilhaften Ausgestaltung ist es zusätzlich mög- lieh, die Dotierung des zweiten Leitungstyp über eine Belegung und einen anschließenden Temperaturschritt in das umgebende Grundmaterial einzutreiben (Figur 4 (c) ) . Um eine definierte Trennung der beiden Leitungsgebiete zu erzielen, sollten in diesem Fall Dotierstoffe mit stark unterschiedlichen Diffusionskoeffizienten eingesetzt werden. Der Vorteil dieses Vorgehens liegt darin, daß bei einem Ausfall eines Grabens 18, beispielsweise verursacht durch einen Partikel während des Lithographieprozesses, das Halbleiterbauelement voll funktionsfähig bleibt. Bei der zuerst genannten Vorgehenswei- se kann es in diesem Bereich hingegen zu einem Zusammenbruch der Sperrspannung und damit zum Ausfall des gesamten Halbleiterbauelements kommen.In an advantageous embodiment, it is additionally possible to drive the doping of the second conductivity type into the surrounding base material via an assignment and a subsequent temperature step (FIG. 4 (c)). In order to achieve a defined separation of the two line areas, dopants with very different diffusion coefficients should be used in this case. The advantage of this procedure is that if a trench 18 fails, for example caused by a particle during the lithography process, the semiconductor component remains fully functional. In contrast, with the first-mentioned procedure, the reverse voltage can break down in this area and the entire semiconductor component can fail.
Anstelle der Auffüllung mit epitaktisch abgeschiedenem Sili- zium kann im Graben 18 auch ein Hohlraum 23 verbleiben, sofern die Grabenwände 20 durch eine Passivierungsschicht 21 bedeckt und der Hohlraum 2, 3 nach oben durch einen Deckel 22, beispielsweise aus Borphosphorsilikatglas (BPSG) , verschlossen wird (Figur 4 (d) ) .Instead of being filled with epitaxially deposited silicon, a cavity 23 can also remain in the trench 18, provided that the trench walls 20 are covered by a passivation layer 21 and the cavity 2, 3 is closed at the top by a cover 22, for example made of borophosphosilicate glass (BPSG) (Figure 4 (d)).
Figur 5 zeigt einige Teilschnitte, anhand derer verschiedene Randvariationen zur Einstellung einer gezielten, "weich" auslaufenden Dotierungskonzentration im Randbereich eines Halbleiterbauelementes dargestellt werden. In Figur 5 wurden der besseren Übersicht heit halber die Strukturen entsprechend den Figuren 1 und 2 nur schematisch angedeutet, da es hier im wesentlichen auf die Geometrie, die Abmessungen und die Abstände der Gräben 18 inbesondere im Randbereich RB des Halbleiterbauelementes ankommt.FIG. 5 shows some partial sections, on the basis of which various edge variations for setting a targeted, “soft” doping concentration in the edge region of a semiconductor component are shown. For the sake of clarity, the structures in accordance with FIGS. 1 and 2 have only been indicated schematically in FIG. 5, since the geometry, the dimensions and the spacing of the trenches 18 are particularly important here, in particular in the edge region RB of the semiconductor component.
Die Gräben 18 können sowohl von der ersten Oberfläche 3 aus, idealerweise selbstjustierend zum eigentlichen Bauelemente- prozeß, also beispielsweise justiert auf die Polysiliziumkan- te, oder aber auch von der Rückseite bzw. der zweiten Oberfläche 6 nach dem Dünnschleifen des Halbleiterkörpers 1 geätzt werden. Dabei kann sowohl anisotropes Ätzen als auch isotropes Ätzen zur Anwendung kommen. Prinzipiell sind auch Gräben 18 möglich, die von der ersten Oberfläche 3 bis zur Rückseite bzw. der zweiten Oberfläche 6 durchgehen (Figur 5(a)). Dotiert man diese Gräben 18 hinreichend hoch, so kann auf die Verwendung der relativ teueren Epitaxiescheiben ver- ziehtet werden.The trenches 18 can both from the first surface 3, ideally self-adjusting to the actual component process, that is, for example, adjusted to the polysilicon edge, or else etched from the rear or the second surface 6 after the semiconductor body 1 has been thinly ground. Both anisotropic etching and isotropic etching can be used. In principle, trenches 18 are also possible, which run through from the first surface 3 to the rear or the second surface 6 (FIG. 5 (a)). If these trenches 18 are doped sufficiently high, the use of the relatively expensive epitaxial disks can be avoided.
Variiert man die Tiefe der Gräben 18 zum Rand hin (Figur 5(a) und (c) ) , so kann im Randbereich RB die Feldstärkeverteilung günstig beeinflußt werden. In Figur 5(c) nimmt die Tiefe tl > t2 > t3 der Gräben 18 zum Rand hin zu kontinuierlich ab. Im Zellenfeld ZF des Bauelementes kann dadurch auch der Ort des Spannungsdurchbruchs festlegen werden.If the depth of the trenches 18 is varied toward the edge (FIGS. 5 (a) and (c)), the field strength distribution can be influenced favorably in the edge area RB. In FIG. 5 (c), the depth t1> t2> t3 of the trenches 18 decreases continuously towards the edge. In this way, the location of the voltage breakdown can also be determined in the cell field ZF of the component.
Ferner wäre es auch denkbar, die Dotierungsbelegung der Grä- ben in radialer oder vertikaler Richtung zu variieren (Figur 5(b)). Wählt man beispielsweise Gräben 18 mit V-förmigem Querschnitt und eine epitaktische Auffüllung dieser Gräben 18, so kann die Form der Gräben 18 bewußt zu einer vertikalen Variation der eingebrachten Ladungsdosis benutzen. Insbeson- dere kann sich hier auch der Böschungswinkel α der Grabenwände zum Rand hin vergrößern.Furthermore, it would also be conceivable to vary the doping assignment of the trenches in the radial or vertical direction (FIG. 5 (b)). For example, if one selects trenches 18 with a V-shaped cross-section and an epitaxial filling of these trenches 18, the shape of the trenches 18 can be used deliberately for a vertical variation of the charge dose introduced. In particular, the slope angle α of the trench walls can also increase towards the edge.
Um einen möglichst graduellen Übergang der Dotierung von nahezu vollständig kompensiert zu deutlich n- oder p-dotiert zu erreichen, bietet es sich an, entweder das Raster bzw. dieIn order to achieve a gradual transition of the doping from almost completely compensated to clearly n- or p-doped, it is advisable to use either the grid or the
Abstände (dl>d2>d3>d4 ) zweier benachbarter Gräben 18 schrittweise zum Rand hin zu erhöhen (Figur 5 (d) ) oder die Durchmesser (rl>r2>r3>r4>r5) der Gräben 18 zum Rand hin zu verringern (Figur 5 (e) ) .Increase distances (dl> d2> d3> d4) of two adjacent trenches 18 step by step towards the edge (FIG. 5 (d)) or decrease the diameter (rl> r2> r3> r4> r5) of the trenches 18 towards the edge ( Figure 5 (e)).
Gegenüber der zuerst genannten Aufbautechnik bietet die sogenannte Trenchtechnik mit geätzten Gräben 18 den Vorteil, daß kleinere Zellraster vorgesehen sein können. Diese kleineren Zellraster können dann eine höhere Dotierung aufweisen, wodurch der flächenhaften Einschaltwiderstand RDS,ON sich signifikant verringert.Compared to the first-mentioned construction technique, the so-called trench technique with etched trenches 18 has the advantage that smaller cell grids can be provided. These smaller cell grids can then have a higher doping, as a result of which the areal switch-on resistance RDS, ON is significantly reduced.
Abschließend sei an dieser Stelle noch ausdrücklich angemerkt, daß selbstverständlich jede der in den Figuren 3 bis 5 beschriebenen Strukturen alleine als auch sehr vorteilhaft in Kombination untereinander herangezogen werden kann, um im Randbereich RB das gewünschte Dotierungsprofil bzw. die gewünschte flächenbezogene Dotierungsverteilung zu erzielen. Finally, it should be expressly noted at this point that each of the structures described in FIGS. 3 to 5 can of course be used alone or very advantageously in combination with one another in order to achieve the desired doping profile or the desired area-related doping distribution in the edge region RB.
BezugszeichenlisteReference list
1 Halbleiterkörper1 semiconductor body
2 Innenzone 3 erste Oberfläche2 inner zone 3 first surface
4 Drainzone4 drain zone
5 Grenzfläche, pn-Übergang5 interface, pn junction
6 zweite Oberfläche6 second surface
7 Drainelektrode 8 Basiszone7 drain electrode 8 base zone
9 Sourcezone9 source zone
10 Sourceelektrode10 source electrode
10' Kontaktloch für die Sourceelektrode10 'contact hole for the source electrode
11 Gateelektrode 12 Gateoxid11 gate electrode 12 gate oxide
13 Feldoxid13 field oxide
14 Raumladungszonenstopper14 space charge zone stoppers
14' Metallelektrode des Raumladungszonenstoppers14 'metal electrode of the space charge zone stopper
14'' Diffusionsgebiet des Raumladungszonenstopper 15 (floatende) Schutzringe14 '' diffusion area of the space charge zone stopper 15 (floating) guard rings
16 Zwischenringzonen16 intermediate ring zones
17 Feldplatte17 field plate
18 Graben18 ditch
19 Grabenboden 20 Grabenwand19 trench floor 20 trench wall
21 Passivierungsschicht im Graben21 passivation layer in the trench
22 Grabendeckel22 trench covers
23 Hohlraum23 cavity
α Böschungswinkel der Grabenwand dl..d4 Abstand zweier benachbarter Gräben, Grabenraster rl..r5 Grabendurchmesser tl..t3 Grabentiefeα Slope angle of the trench wall dl..d4 distance between two neighboring trenches, trench grid rl..r5 trench diameter tl..t3 trench depth
OB offener Bereich im RandbereichOB open area in the edge area
RB RandbereichRB edge area
ZI..Z3 Zellen ZF ZellenfeldZI..Z3 cells IF cell field
D DrainanschlußD drain connection
G GateanschlußG gate connection
S Sourceanschluß S source connection
Claims
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19748524 | 1997-11-03 | ||
| DE19748524 | 1997-11-03 | ||
| PCT/DE1998/003197 WO1999023703A1 (en) | 1997-11-03 | 1998-11-02 | High voltage resistant edge structure for semiconductor elements |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1029358A1 true EP1029358A1 (en) | 2000-08-23 |
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ID=7847469
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP98962198A Ceased EP1029358A1 (en) | 1997-11-03 | 1998-11-02 | High voltage resistant edge structure for semiconductor elements |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US6870201B1 (en) |
| EP (1) | EP1029358A1 (en) |
| JP (1) | JP3628613B2 (en) |
| WO (1) | WO1999023703A1 (en) |
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| JP2001522145A (en) | 2001-11-13 |
| US6870201B1 (en) | 2005-03-22 |
| WO1999023703A1 (en) | 1999-05-14 |
| JP3628613B2 (en) | 2005-03-16 |
| WO1999023703A9 (en) | 1999-09-02 |
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