TWI422030B - Contant current semiconductor device with schottky barrier structure - Google Patents

Description

Constant current semiconductor components with Schottky Barrier

The present invention relates to a semiconductor-related technology, and more particularly to a constant current semiconductor device having a Schottky Barrier using a metal/semiconductor contact principle, the structure/characteristics of which have a Schottky diode. The difference.

The basic principle of a PN diode made of a semiconductor substrate is to form a P-type and N-type semiconductor substrate by a semiconductor diffusion technique, and to form an external package by electrodes, respectively; The use condition is a rectifier (Rectifier) used by a current flowing from a P-type region to an N-type region and passing through in a reverse direction. In addition, the Schottky diode is a metal-semiconductor-bonded Schottky barrier that also has a unidirectional current through current and a non-passing current in the other direction. It is especially used in the conversion of AC power to DC power for use in electronic circuits for general electronic products.

In addition to being a rectifier, the above-mentioned PN diode/Schottky diode is also classified into a Zener Diode and a Switching Diode depending on its function and material properties. , Photo Diode and so on. In addition, LEDs (Light Emitting Diodes) have been widely used in various electronic products to save energy, light weight and shortness. In recent years, LEDs have developed high-brightness (HI-POWER LED) technology. In place of the traditional trend of various lighting illuminators, the use of LEDs can be seen in industrial, household lighting, traffic roads, and the like.

In the above LED and general application circuit design, it is more common to use a constant voltage power supply to perform constant voltage control on the LED array. As long as the output voltage of the power supply circuit meets the rated voltage of the LED array, the LED array can be driven. However, LED arrays have different numbers and voltage values depending on the place used. It is necessary to add an excessive series voltage to the power supply circuit according to the number of LEDs and the matching series current limiting resistor. Power loss, and when a certain part of the LED array is damaged in the LED array, the overall voltage will decrease and the current will increase, causing other LED units to be damaged one after another; in addition, the constant voltage power supply is often caused by voltage instability. LEDs have problems with flicker when in use.

In order to overcome the above problems, the theoretical use of constant current power supply control method is better than constant voltage power supply control, but the current implementation of constant current control is mostly composed of complex integrated circuit design, and the cost is very high; The method is made by using complex PN junction transistor plane technology, which not only has poor yield, can not be mass produced, and is not easy to generate large driving current.

In view of this, the present inventors have accumulated years of research and practical experience in the field of semiconductor technology, and have invented a "constant current semiconductor device having a Schottky Barrier" in order to improve the disadvantages of the prior art.

It is an object of the present invention to provide a constant current semiconductor device having a Schottky Barrier having a Schottky barrier and a constant current characteristic, which has a low starting voltage and is easy to process. Separating a plurality of semiconductor element elements and combining them into a constant current semiconductor element suitable for a large driving current or an array designed as a constant current semiconductor element (Arrays); its structure/characteristics and Schottky II The polar body is different.

In order to achieve the above object, the present invention "a constant current semiconductor device having a Schottky Barrier" is formed on an N-type or P-type semiconductor epitaxial layer surface which is grown on a semi-insulating substrate. A first metal electrode end and a second metal electrode end are provided for electrical connection, wherein the first metal electrode end and the epitaxial layer include a first Ohmic Contact section and a Schottky a Schottky Contact section, a second ohmic contact section between the second metal electrode end and the epitaxial layer, and the Schottky contact section between the first and second ohmic contact sections Separating from the second ohmic contact section, the semiconductor element has a Schottky barrier lower starting voltage at the Schottky contact section, and the thickness, material, and thickness of the epitaxial layer The distance between the first and second metal electrode terminals is designed to have a constant current function, and its structure/characteristic is different from that of the Schottky diode.

A second embodiment of the present invention is an N-type or P-type epitaxial layer surface grown on a semi-insulating substrate, and is provided with a first metal electrode end electrically connectable and isolated from each other. And a second metal electrode end, and the epitaxial layer is provided with a recessed stage platform (Recessed Mesa) between the first and second metal electrode ends; wherein the first metal electrode end and the epitaxial layer are a first 殴m Contacting an (Ohmic Contact) section, and the first metal electrode end extends along the surface of the epitaxial layer to the stage platform, and is a Schottky Contact section, a second metal electrode and an epitaxial layer Between the layers is a second 接触 contact section, and the second 接触 接触 contact section and the Schottky contact section are isolated from each other, so that the semiconductor element has a Schottky barrier at the Schottky contact section The characteristics of the lower starting voltage, and the constant current function by the thickness and material of the epitaxial layer and the depth or width of the platform at this stage, and its structure/characteristics are different from those of the Schottky diode.

When the constant current semiconductor component is implemented, the first metal electrode end and the second metal electrode end are electrically connected, so that the subsequent process can first fix the semiconductor component on the bracket, and the first and second metal electrode ends and the bracket When the upper terminal is electrically connected, a constant current diode can be formed after the Flip-Chip and the division process. Of course, it is also one of the feasible embodiments that the first and second metal electrode ends are directly exposed to the outside as the terminals of the SMD (Surface Adhesive Element) if a suitable material is selected.

In addition, if the above-mentioned plurality of constant current semiconductor devices having Schottky barriers are isolated from each other directly on a large-area wafer in the process, the photomask and the photographic technology in the process can be utilized. The integrated body is combined into a constant current semiconductor element suitable for a large driving current. It is also possible to design a plurality of constant current semiconductor components with Schottky barriers by using a bracket, and then form a current-regulating device array (Arrays) through a flip chip package (Flip-Chip), which not only saves man-hours, but also is easy to design and manufacture. The advantages are as follows, and when the structure is used to dissipate heat on the surface, the heat dissipation is particularly good, and the utility model has a wider application range.

Other embodiments of the present invention are further described below. In the process, the first and second metal electrode ends are electrically connected and fixed to the terminals on the bracket for convenience, and may be implemented at the first and second metal electrode ends. A solder ball is placed on each surface. If the first and second metal electrode terminals are directly exposed to the outside as terminals of the SMD (Surface Adhesive Element) as described above, the solder balls can also be soldered to the PC board or other substrate as SMT (Surface Adhesion Technology). solder.

In order to increase the product yield, an insulating protective layer may be disposed between the first and second metal electrode ends to ensure an insulation state between the first and second metal electrode ends.

In order to achieve the effect of the above-mentioned large-scale constant current element and constant current element array (Arrays), a plurality of constant current semiconductor elements having Schottky barriers on the same wafer can be isolated from each other by an Isolation layer. Diffusion processes are applied to both sides to form an isolation layer.

In the process, in order to subsequently divide a plurality of fixed current semiconductor components having Schottky barriers on the same wafer, a Mesa etching process may be applied on both sides of the epitaxial layer to form isolated trenches on both sides. And a passive protective layer (Passivation) formed by the glass or the oxide layer is filled in the isolation trenches on both sides.

In implementation, the formation of the aforementioned stage platform may be performed simultaneously or in stages with the Mesa etching process; the passive protective layer may be implemented in the same process or in stages as the foregoing insulating protective layer.

Compared with the prior art, the present invention has a Schottky Barrier constant current semiconductor component, and has a structure/characteristics in addition to a low starting voltage and a constant current characteristic of the Schottky barrier. Different from the Schottky diode, and it is easy to isolate several semiconductor components in the process, and combine them into a constant current semiconductor component suitable for a large driving current, thereby saving labor and time. Many advantages such as design and manufacture; in use, because the structure is heat-dissipated on the surface, its heat dissipation is particularly good, and it has a wider application range.

In the following, according to the technical means of the present invention, embodiments suitable for the present invention are listed, and the following description is made in conjunction with the following description: As shown in the first figure, the present invention has a Schottky Barrier constant current semiconductor component. 100 is disposed on an surface of an N-type or P-type semiconductor epitaxial layer 20 grown on a semi-insulating substrate 10, and is provided with a first metal electrode end 30 and a second metal electrode end 40 for electrical connection. Wherein, the first metal electrode end 30 and the epitaxial layer 20 include a first Ohmic Contact section 31 and a Schottky Contact section 32, and the second Between the metal electrode terminal 40 and the epitaxial layer 20 is a second contact region 41 such that the Schottky contact portion 32 is located between the first and second contact regions 31, 41, and The Schottky contact section 32 and the second ohmic contact section 41 are isolated from each other such that the semiconductor element 100 has a Schottky barrier lower starting voltage characteristic at the Schottky contact section 32, and Thickness, material of the epitaxial layer 20 and between the first and second metal electrode ends 30, 40 Design includes a constant current from the function and the structure / characteristics of the Schottky diode differ.

As shown in the second figure, the semiconductor device 100 of the second embodiment of the present invention is provided on the surface of an N-type or P-type semiconductor epitaxial layer 20 grown on the semi-insulating substrate 10. A first metal electrode end 30 and a second metal electrode end 40 are electrically connected, and the epitaxial layer 20 is provided with a recessed stage platform (Recessed Mesa) 21 between the first and second metal electrode ends 30, 40. Wherein the first metal electrode end 30 and the epitaxial layer 20 are a first Ohmic Contact section 31, and the first metal electrode end 30 is bent down along the surface of the epitaxial layer 20 to the stage. a recessed portion of the platform 21, a bottom portion of the downwardly extending portion of the first metal electrode end 30 and a top surface of the stage platform 21 is a Schottky Contact section 32; and the second metal electrode 40 is Between the epitaxial layers 20 is a second ohmic contact section 41, and the second ohmic contact section 41 is isolated from the aforementioned Schottky contact section 32, so that the semiconductor element 100 is in the Schottky contact area. Segment 32 has the characteristics of a lower start-up voltage of the Schottky barrier and is controlled by epitaxy 20 thickness, the material and the depth or width of the stage platform 21 is designed to have constant current function, and the structure / characteristics of the Schottky diode differ.

The semiconductor device 100 has a low start-up voltage characteristic and a constant current function, and its characteristic curve is as shown in the third figure: when the semiconductor element is at a lower voltage, the resistance characteristics between the two electrodes of the segment A are exhibited. Because the voltage of Schottky is controlled, that is, the Depletion Layer under the Schottky barrier is changed, and when it is V _KP , the linear resistance characteristic is turned, that is, the cut-off conductive pipe current is turned into saturation. Current I _P (ie, segment B in the figure); at this time, the thickness, material, and distance between the first and second metal electrode terminals, or the depth and width of the stage platform, are designed by the foregoing design. It is possible to control the characteristic curve to enter the breakdown phase C as the voltage rises (V SP~VB), and the low start voltage (V KP) and the constant current (IP) can be achieved by the design of the Schottky barrier. ) The effect.

Moreover, the above-described constant current semiconductor device having the Schottky Barrier of the present invention can achieve an effect by experiments. For example, the semi-insulating substrate has a resistivity of 20 Ω-cm and an epitaxial layer of about 2 Ω-cm. 10μm, Schottky barrier width of about 2μm, semiconductor component size of about 300~600μm X 300~600μm square, can be made into a constant current semi-conductive component with a voltage between 10V-100V and about 20mA.

When the constant current semiconductor component is implemented, the first metal electrode end and the second metal electrode end are electrically connected, so that the subsequent process can first fix the semiconductor component on the bracket, and the first and second metal electrode ends and the bracket When the upper terminal is electrically connected, a constant current diode can be formed after the Flip-Chip and the division process. Of course, if the first and second metal electrode ends are directly exposed to the outside as the terminals of the SMD (Surface Adhesive Element), it is also one of the feasible embodiments; the bracket, the terminal, and the flip chip package are used. , the division process and the SMD are all known techniques, and are not described here.

In addition, if the above-mentioned plurality of constant current semiconductor devices having Schottky barriers are directly isolated from each other on a large-area wafer in the process, the process can be designed by using the mask and the photographic technology in the process. The integrated body is combined into a constant current semiconductor element suitable for a large driving current. It is also possible to design a plurality of constant current semiconductor components with Schottky barriers by using a bracket, and then form a current-regulating device array (Arrays) through a flip chip package (Flip-Chip), which not only saves man-hours, but also is easy to design and manufacture. It has the advantages, and the heat dissipation is particularly good due to the heat dissipation of the structure on the surface during use, and has a wider application range.

Further embodiments of the present invention are further described below. As shown in the fourth and fifth figures, in order to facilitate the fixing of the semiconductor element to the holder, a solder may be respectively disposed on the surfaces of the first and second metal electrode ends 30, 40. The ball 50, which can be soldered to the terminal on the bracket by the solder ball 50, is electrically connected. If the first and second metal electrode terminals 30, 40 are directly exposed to the outside as the terminals of the SMD (Surface Adhesive Element), the solder ball 50 can also be soldered to the PC board as an SMT (Surface Adhesion Technology) or Solder on other substrates.

In the process, in order to increase the product yield, an insulating protective layer 60 may be disposed between the first and second metal electrode ends 30, 40 to ensure the first and second metal electrode ends 30, 40. The state of insulation between.

In the process, in order to achieve the above-mentioned large-scale constant current element and constant current element array (Arrays) process, a plurality of fixed-current semiconductor elements 100 having Schottky barriers on the same wafer are isolated from each other (Isolation). A diffusion process is applied to both sides of the epitaxial layer 20 to form an isolation layer 70 between the epitaxial layers 20, 20' of the two adjacent semiconductor elements 100, 100'. The isolation layer 70 allows two phases. The adjacent semiconductor elements 100, 100' are individually isolated from each other to achieve the above-mentioned integrated body assembly into a constant current semiconductor element suitable for a large driving current, and after a subsequent process, a large-sized constant current element suitable for a large current is formed. Constant current element arrays (Arrays).

As shown in the first and second figures, in the process, in order to carry out the dividing process of the plurality of constant current semiconductor elements 100 having the Schottky barrier on the same wafer, the high stage can be applied on both sides of the epitaxial layer 20 ( Mesa) etching process to form two isolation trenches 22, and a passive protective layer 23 formed by filling a glass or an oxide layer on the two isolation trenches 22, so that A passive protection effect is formed on both sides of the semiconductor component 100 after each divided process.

In implementation, the formation of the stage stage 21 can be performed simultaneously or in stages with the Mesa etching process; and the passive protective layer 23 can be implemented in the same process or in stages as the insulating protective layer 60 to save man-hours and Manufacturing process.

The above names are intended to describe the technical content of the present invention, and are not intended to limit the scope of the present invention. All equivalent component conversions and substitutions made in accordance with the creative spirit of this case should be covered in the scope of this case. This statement.

100. . . Semiconductor component

10. . . Semi-insulating substrate

20. . . Epitaxial layer

twenty one. . . Stage platform

twenty two. . . Isolation trench

twenty three. . . Passive protective layer

30. . . First metal electrode end

31. . . First 接触m contact section

32. . . Schottky Contact Section

40. . . Second metal electrode end

41. . . Second 接触m contact section

50. . . Solder ball

60. . . Insulating protective layer

70. . . Isolation layer

The first figure is a side cross-sectional structural view of a first embodiment of the present invention.

The second drawing is a side cross-sectional structural view of a second embodiment of the present invention.

The third figure is a schematic diagram showing the characteristic curves of Schottky barrier and constant current in the implementation of the present invention.

The fourth figure is a schematic structural view of another embodiment of the first embodiment of the present invention.

The fifth drawing is a schematic structural view of another embodiment of the second embodiment of the present invention.

100. . . Semiconductor component

10. . . Semi-insulating substrate

20. . . Epitaxial layer

twenty two. . . Isolation trench

twenty three. . . Passive protective layer

30. . . First metal electrode end

31. . . First 接触m contact section

32. . . Schottky Contact Section

40. . . Second metal electrode end

41. . . Second 接触m contact section

60. . . Insulating protective layer

Claims (9)

A constant current semiconductor device having a Schottky barrier is formed on a surface of an N-type or P-type semiconductor epitaxial layer grown on a semi-insulating substrate, and is provided with a first metal electrode terminal and a second for electrical connection a metal electrode end, and the epitaxial layer is provided with a recessed stage platform between the first and second metal electrode ends; the first metal electrode end and the epitaxial layer are a first contact region, and the first A metal electrode end is bent downward along the surface of the epitaxial layer to a recessed portion of the stage platform, and a bottom portion of the downward extending portion of the first metal electrode end and a top surface of the stage platform is a Schottky contact section, and the second metal Between the electrode and the epitaxial layer is a second ohmic contact section, and the second ohmic contact section is isolated from the Schottky contact section. A fixed current semiconductor device having a Schottky barrier according to the first aspect of the patent application, wherein the stage platform is formed by a high etching process. A constant current semiconductor device having a Schottky barrier according to the first aspect of the invention, wherein the first and second metal electrode ends are further provided with a solder ball on each surface. A constant current semiconductor device having a Schottky barrier according to the first aspect of the invention, wherein an insulating protective layer is further disposed between the first and second metal electrode ends. A fixed current semiconductor device having a Schottky barrier according to the first aspect of the invention, wherein an isolation layer is further disposed on both sides of the epitaxial layer to isolate two adjacent semiconductor elements from each other in the process. A constant current semiconductor element having a Schottky barrier as described in claim 5 And wherein the isolation layer is formed by a diffusion process. A constant current semiconductor device having a Schottky barrier according to the first aspect of the invention, wherein an isolation trench is further provided on both sides of the epitaxial layer. A fixed current semiconductor device having a Schottky barrier according to the seventh aspect of the invention, wherein the isolation trench is filled with a passive protective layer. A fixed current semiconductor device having a Schottky barrier according to the seventh aspect of the invention, wherein the isolation trench is formed by a high etching process.