TWI780566B - Semiconductor strcuture - Google Patents

Abstract

A semiconductor structure including a substrate, a semiconductor layer, a floating field ring structure, and a conductive layer is provided. The semiconductor layer is disposed on the substrate. The semiconductor layer has a first conductive type. The floating field ring structure is located in the semiconductor layer. The floating field ring structure includes floating field rings. The floating field ring has a second conductive type. The conductive layer is located on one side of the floating field ring. Two adjacent floating field rings are set as a group, and the conductive layer is not disposed between at least one group of the floating field rings.

Description

semiconductor structure

The present invention relates to a semiconductor structure, and more particularly to a semiconductor structure having a floating field ring (FFR).

Some semiconductor devices (eg, power devices) are prone to breakdown at the edge of the main junction. The current solution is to increase the breakdown voltage of the semiconductor element by means of a floating field ring surrounding the semiconductor element region, so as to prevent the breakdown phenomenon. However, how to further increase the breakdown voltage of semiconductor devices is the goal of ongoing efforts.

The invention provides a semiconductor structure, which can increase the breakdown voltage of semiconductor elements.

The invention proposes a semiconductor structure, including a base, a semiconductor layer, a floating field ring structure and a conductor layer. The semiconductor layer is disposed on the substrate. The semiconductor layer has a first conductivity type. The floating body field ring structure is located in the semiconductor layer. The floating body field ring structure includes a plurality of floating body field rings. The floating body field ring has a second conductivity type. The conductor layer is located on one side of the field ring of the floating body. Two adjacent floating body field rings are taken as a group, and no conductor layer is provided between at least one group of floating body field rings.

According to an embodiment of the present invention, in the above semiconductor structure, two adjacent groups of floating body field rings may share one floating body field ring.

According to an embodiment of the present invention, in the above semiconductor structure, the conductor layer may be located between two adjacent floating body field rings.

According to an embodiment of the present invention, in the above semiconductor structure, the conductive layer can be a doped region, metal, doped polysilicon, metal silicide or a combination thereof.

According to an embodiment of the present invention, in the above semiconductor structure, the conductor layer may be connected to the floating body field ring structure.

According to an embodiment of the present invention, in the above semiconductor structure, the conductive layer may not be connected to the floating body field ring structure.

According to an embodiment of the present invention, in the above semiconductor structure, the bottom surface of the conductive layer may be higher than the bottom surface of the floating body field ring.

According to an embodiment of the present invention, in the above semiconductor structure, the entire conductor layer may be located in the semiconductor layer.

According to an embodiment of the present invention, in the above semiconductor structure, the conductor layer may be located on the top surface of the semiconductor layer.

According to an embodiment of the present invention, in the above semiconductor structure, a part of the conductor layer can be located in the semiconductor layer, and another part of the conductor layer can protrude from the top surface of the semiconductor layer.

According to an embodiment of the present invention, in the above semiconductor structure, the number of conductive layers may be one.

According to an embodiment of the present invention, in the above semiconductor structure, the number of conductive layers may be multiple.

According to an embodiment of the present invention, in the above semiconductor structure, the base may include a semiconductor element region. The floating body field ring structure can surround the semiconductor element region. The semiconductor structure may further include semiconductor elements. The semiconductor device may include a first doped region and a second doped region. The first doped region is located in the semiconductor layer of the semiconductor element region. The first doped region may have a second conductivity type. The second doped region is located in the base and adjacent to the semiconductor layer. The second doped region may have the first conductivity type.

According to an embodiment of the present invention, in the above semiconductor structure, the semiconductor device may further include a well region. The well region is located in the semiconductor layer in the semiconductor element region. The well region may have a second conductivity type. The first doped region is in the well region.

According to an embodiment of the present invention, in the above semiconductor structure, the semiconductor element may further include a third doped region. The third doping region is located in the semiconductor layer on the side of the floating body field ring structure away from the semiconductor element region.

According to an embodiment of the present invention, the above semiconductor structure may further include a fourth doped region. The fourth doping region is located in the semiconductor layer between the floating body field ring structure and the third doping region. The fourth doped region may have the first conductivity type.

Based on the above, in the semiconductor structure proposed by the present invention, the conductor layer is located on one side of the floating body field ring, thereby changing the energy band generated by the floating body field ring structure and causing interference to the electric field. Furthermore, an electric field concentration may be generated at the conductor layer. Therefore, the effect of dispersing the electric field can be achieved by the conductive layer, thereby increasing the breakdown voltage of the semiconductor device. In addition, since the semiconductor structure proposed by the present invention can increase the breakdown voltage of the semiconductor element, even if the area of the floating body field ring structure is reduced, the same breakdown voltage as the prior art can be maintained, and the element size can be smaller. On the other hand, the manufacturing process of the semiconductor structure proposed by the present invention can be easily integrated with the existing manufacturing process.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

FIG. 1 is a top view of a semiconductor structure according to an embodiment of the present invention. In FIG. 1 , some components in FIG. 2A are omitted to clearly describe the configuration relationship among the components in FIG. 1 . 2A is a cross-sectional view of the semiconductor structure along the line I-I' in FIG. 1 . 2B to 2I are cross-sectional views of semiconductor structures along the line I-I' in FIG. 1 according to other embodiments of the present invention. In FIGS. 2A to 2I , the same or similar components are denoted by the same symbols.

Referring to FIG. 1 and FIG. 2A , the semiconductor structure 10 includes a substrate 100 , a semiconductor layer 102 , a floating body field ring structure 104 and a conductive layer 106 . The substrate 100 can be a semiconductor substrate, such as a silicon substrate. In addition, the substrate 100 may include a semiconductor element region R. Referring to FIG.

The semiconductor layer 102 is disposed on the substrate 100 . The material of the semiconductor layer 102 is, for example, semiconductor materials such as epitaxial silicon. The semiconductor layer 102 has a first conductivity type (eg, N type). In addition, the first conductivity type and the second conductivity type may be different conductivity types. The first conductivity type and the second conductivity type may be one and the other of N type and P type, respectively. In this embodiment, the first conductivity type is N-type as an example, and the second conductivity type is P-type as an example, but the present invention is not limited thereto. In other embodiments, the first conductivity type may be P-type, and the second conductivity type may be N-type.

The floating body field ring structure 104 is located in the semiconductor layer 102 . The floating body field ring structure 104 can surround the semiconductor device region R ( FIG. 1 ). The floating body field ring structure 104 includes a plurality of floating body field rings 104a. Take two adjacent floating body field rings 104a as a group. In this embodiment, the floating body field ring structure 104 may include multiple sets of floating body field rings 104a, but the present invention is not limited thereto. Two adjacent groups of floating body field rings 104a may share one floating body field ring 104a. For example, since two adjacent floating body field rings 104a can form a group of floating body field rings 104a, seven floating body field rings 104a in FIG. 2A can form six groups of floating body field rings 104a, but the present invention The number and the number of groups of floating body field rings 104a are not limited thereto. In other embodiments, the floating body field ring structure 104 may only include one set of floating body field rings 104a, that is, the floating body field ring structure 104 may only include two adjacent floating body field rings 104a. The floating body field ring 104a has a second conductivity type (eg, P-type). For example, the floating body field ring 104a can be a doped region of the second conductivity type (eg, P-type). In addition, the width W of the plurality of floating body field rings 104a may be the same or different from each other.

The conductive layer 106 is located on one side of the floating body field ring 104a, thereby changing the energy band generated by the floating body field ring structure 104 and causing interference to the electric field. In addition, electric field concentration can be generated at the conductive layer 106 to achieve the effect of dispersing the electric field, thereby increasing the breakdown voltage. In some embodiments, when the breakdown voltage is optimized, another current path is generated near the conductor layer 106 to achieve the effect of spreading the current.

In addition, two adjacent floating body field rings 104a are taken as a group, and no conductor layer 106 is provided between at least one group of floating body field rings 104a. For example, as shown in FIG. 2A , no conductor layer 106 is provided between the five sets of floating body field rings 104 a, but the invention is not limited thereto. As long as there is no conductor layer 106 between at least one set of floating body field rings 104a, it falls within the scope of the present invention. In addition, the bottom surface BS1 of the conductive layer 106 may be higher than the bottom surface BS2 of the floating body field ring 104a.

As shown in FIG. 2A , the conductor layer 106 may be located between two adjacent floating body field rings 104a, but the invention is not limited thereto. In addition, the conductor layer 106 can be located between any set of floating body field rings 104a. For example, the conductive layer 106 can be located between the left second group of floating body field rings 104a. In some other embodiments, as shown in FIG. 2B , the conductor layer 106 may not be located between two adjacent floating body field rings 104a, but located in the innermost (eg, closest to the semiconductor element region R) floating A side of the body field ring 104a close to the semiconductor device region R. In some other embodiments, the conductive layer 106 may be located on the outermost (eg, furthest away from the semiconductor device region R) side of the floating body field ring 104 a away from the semiconductor device region R (not shown). In addition, when the position of the conductive layer 106 is closer to the semiconductor device region R, the effect of increasing the breakdown voltage is better.

As shown in FIG. 2A , the entire conductive layer 106 may be located in the semiconductor layer 102 , that is, the conductive layer 106 may not protrude from the top surface TS of the semiconductor layer 102 , but the invention is not limited thereto. The conductive layer 106 can be a doped region, a metal (such as aluminum, copper, gold, silver, etc. or alloys thereof), doped polysilicon, metal silicide (such as cobalt silicide or nickel silicide, etc.), or a combination thereof. In addition, when the conductive layer 106 is a doped region, the doped region may have a second conductivity type (eg, P-type). In other embodiments, as shown in FIG. 2C, if the conductive layer 106 is a metal silicide formed by a self-aligned-silicide (salicide) process, the entire conductive layer 106 can be on the surface of the opening OP in the semiconductor layer 102 .

In other embodiments, as shown in FIG. 2D , the conductive layer 106 may be located on the top surface TS of the semiconductor layer 102 . In this case, the conductive layer 106 can be metal (such as aluminum, copper, gold, silver, etc. metals or their alloys), doped polysilicon or metal silicide (such as cobalt silicide or nickel silicide, etc.), or a combination thereof.

In other embodiments, as shown in FIG. 2E , a part of the conductive layer 106 may be located in the semiconductor layer 102 , and another part of the conductive layer 106 may protrude from the top surface TS of the semiconductor layer 102 . In this case, the conductive layer 106 can be a doped region, a metal (such as aluminum, copper, gold, silver or other metals or alloys thereof), doped polysilicon or metal silicide (such as cobalt silicide or nickel silicide, etc.) or a combination thereof. In some embodiments, the conductive layer 106 located in the semiconductor layer 102 and the conductive layer 106 protruding from the top surface TS of the semiconductor layer 102 may be made of the same material. In some other embodiments, the conductive layer 106 located in the semiconductor layer 102 and the conductive layer 106 protruding from the top surface TS of the semiconductor layer 102 may be made of different materials.

As shown in FIG. 2A , the number of conductor layers 106 may be one, but the invention is not limited thereto. In some other embodiments, as shown in FIG. 2F , the number of conductor layers 106 may be multiple, and is not limited to the number in FIG. 2F . In FIG. 2F , the plurality of conductive layers 106 can adopt the configuration of FIG. 2A , that is, the plurality of conductive layers 106 can all be located in the semiconductor layer 102 , but the invention is not limited thereto. In some other embodiments, the plurality of conductive layers 106 can adopt the configuration shown in FIG. 2D , that is, the plurality of conductive layers 106 can all be located on the top surface TS of the semiconductor layer 102 (not shown). In some other embodiments, the plurality of conductor layers 106 can be configured in the manner shown in FIG. show). In other embodiments, the plurality of conductor layers 106 can adopt any combination of the configurations in FIG. 2A , FIG. 2D and FIG. 2E . For example, at least one conductive layer 106 can be located entirely in the semiconductor layer 102, at least one conductive layer 106 can be located on the top surface TS of the semiconductor layer 102, and at least one conductive layer 106 can be partially located in the semiconductor layer 102 and A portion protrudes from a top surface TS (not shown) of the semiconductor layer 102 .

As shown in FIGS. 2A to 2F , the conductive layer 106 may be connected to the floating body field ring structure 104 . For example, the conductive layer 106 can be connected to the adjacent floating field ring 104a, but the invention is not limited thereto. In other embodiments, the conductor layer 106 may not be connected to the floating body field ring structure 104 . For example, referring to FIG. 2A and FIG. 2G, the conductor layer 106 and the floating body field ring 104a in FIG. 2A can be arranged at a distance to form a conductor not connected to the floating body field ring structure 104 in FIG. 2G Layer 106. In some other embodiments, the conductor layer 106 in FIGS. 2B to 2F may also be configured not to be connected to the floating body field ring structure 104 .

In some other embodiments, the conductor layer 106 may pass through at least one floating body field ring structure 104a. As shown in FIG. 2H , the conductive layer 106 passes through a floating body field ring structure 104 a, but the invention is not limited thereto. In other embodiments, as shown in FIG. 2I , the conductive layer 106 may pass through two floating body field ring structures 104 a.

In addition, the semiconductor structure 10 may further include a semiconductor element 108 . The semiconductor device 108 can be an active device, such as a power device. In some embodiments, the semiconductor element 108 is, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET), a diode (diode) or an insulated gate bipolar transistor (insulated gate bipolar). transistor, IGBT), etc.

The semiconductor device 108 can include a doped region 110 and a doped region 112 . The doped region 110 is located in the semiconductor layer 102 of the semiconductor device region R. As shown in FIG. The doped region 110 may have a second conductivity type (eg, P type). The doped region 112 is located in the substrate 100 and adjacent to the semiconductor layer 102 . In some embodiments, the doped regions 112 may be uniformly distributed throughout the substrate 100 . The doped region 112 may have a first conductivity type (eg, N type).

In addition, the semiconductor device 108 may further include at least one of the well region 114 and the doped region 116 . The well region 114 is located in the semiconductor layer 102 of the semiconductor device region R. As shown in FIG. The well region 114 may have a second conductivity type (eg, P type). The doped region 110 is located in the well region 114 . In addition, the doping concentration of the doped region 110 may be greater than the doping concentration of the floating body field ring 104 a and the doping concentration of the well region 114 . The doped region 116 is located in the semiconductor layer 102 on the side of the floating body field ring structure 104 away from the semiconductor device region R. On the other hand, the semiconductor device 108 may further include other required components according to the device type, and the description thereof is omitted here.

In some embodiments, according to the type of the semiconductor device 108 , the doped region 116 can be of the first conductivity type (eg, N-type) or the second conductivity type (eg, P-type). In some embodiments, if the doped region 116 is of the first conductivity type (eg, N type), the doped region 116 can be coupled to the doped region 112 , but the invention is not limited thereto.

In addition, the semiconductor structure 10 may further include a doped region 118 . The doped region 118 is located in the semiconductor layer 102 between the floating body field ring structure 104 and the doped region 116 . The doped region 118 may have a first conductivity type (eg, N type). The doped region 118 can serve as a channel stop region.

Based on the above-mentioned embodiments, in the semiconductor structure 10 , the conductive layer 106 is located on one side of the floating body field ring 104 a, thereby changing the energy band generated by the floating body field ring structure 104 and causing interference to the electric field. Therefore, the conductive layer 106 can achieve the effect of dispersing the electric field, thereby increasing the breakdown voltage of the semiconductor device 108 . In addition, since the semiconductor structure 10 can increase the breakdown voltage of the semiconductor device 108 , even if the area of the floating body field ring structure 104 is reduced, the same breakdown voltage as the prior art can be maintained, and the device size can be smaller. On the other hand, the manufacturing process of the semiconductor structure 10 can be easily integrated with the existing manufacturing process.

To sum up, in the semiconductor structure of the above embodiments, the effect of electric field dispersion can be achieved by the conductor layer on one side of the field ring of the floating body, so the breakdown voltage of the semiconductor device can be increased.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention should be defined by the scope of the appended patent application.

10: Semiconductor Structure 100: base 102: Semiconducting layer 104: Floating Body Field Ring Structure 104a: Floating Body Field Ring 106: conductor layer 108: Semiconductor components 110, 112, 116, 118: doped regions 114: Well Area BS1, BS2: Bottom OP: open R: Semiconductor element area TS: top surface W: width

FIG. 1 is a top view of a semiconductor structure according to an embodiment of the present invention. 2A is a cross-sectional view of the semiconductor structure along the line I-I' in FIG. 1 . 2B to 2I are cross-sectional views of semiconductor structures along the line I-I' in FIG. 1 according to other embodiments of the present invention.

10: Semiconductor Structure 100: base 102: Semiconducting layer 104: Floating Body Field Ring Structure 104a: Floating Body Field Ring 106: conductor layer 108: Semiconductor components 110, 112, 116, 118: doped regions 114: Well Area BS1, BS2: Bottom R: Semiconductor element area TS: top surface W: width

Claims (16)

A semiconductor structure comprising: base; a semiconductor layer disposed on the substrate and having a first conductivity type; a floating body field ring structure located in the semiconductor layer and including a plurality of floating body field rings, wherein the floating body field rings have a second conductivity type; and The conductor layer is located on one side of the floating body field ring, wherein two adjacent floating body field rings are used as a group, and the conductor is not provided between at least one group of the floating body field rings Floor. The semiconductor structure according to claim 1, wherein two adjacent groups of floating body field rings share one floating body field ring. The semiconductor structure according to claim 1, wherein the conductor layer is located between two adjacent floating body field rings. The semiconductor structure of claim 1, wherein the conductive layer comprises doped regions, metal, doped polysilicon, metal silicide, or a combination thereof. The semiconductor structure as claimed in claim 1, wherein the conductor layer is connected to the floating body field ring structure. The semiconductor structure as claimed in claim 1, wherein the conductor layer is not connected to the floating body field ring structure. The semiconductor structure according to claim 1, wherein the bottom surface of the conductor layer is higher than the bottom surface of the floating body field ring. The semiconductor structure of claim 1, wherein the entire conductor layer is located in the semiconductor layer. The semiconductor structure of claim 1, wherein the conductor layer is located on the top surface of the semiconductor layer. The semiconductor structure according to claim 1, wherein a part of the conductive layer is located in the semiconductor layer, and another part of the conductive layer protrudes from the top surface of the semiconductor layer. The semiconductor structure according to claim 1, wherein the number of said conductor layer is one. The semiconductor structure according to claim 1, wherein the number of the conductor layers is multiple. The semiconductor structure according to claim 1, wherein the base comprises a semiconductor element region, the floating body field ring structure surrounds the semiconductor element region, and the semiconductor structure further comprises: Semiconductor components, including: a first doped region located in the semiconductor layer of the semiconductor element region and having the second conductivity type; and A second doped region is located in the base and adjacent to the semiconductor layer, wherein the second doped region has the first conductivity type. The semiconductor structure as claimed in claim 13, wherein the semiconductor element further comprises: A well region is located in the semiconductor layer of the semiconductor element region and has the second conductivity type, wherein the first doped region is located in the well region. The semiconductor structure as claimed in claim 13, wherein the semiconductor element further comprises: The third doping region is located in the semiconductor layer on the side of the floating body field ring structure away from the semiconductor element region. The semiconductor structure as claimed in claim 15, further comprising: The fourth doped region is located in the semiconductor layer between the floating body field ring structure and the third doped region, and has the first conductivity type.

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