# US 12,604,504 B2 · Shielding structure for silicon carbide devices

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,604,504 B2
- Document ID: US12604504B2
- Status: Granted
- Kind: B2
- Application number: 17/533,513
- Filed: 2021-11-23
- Published: 2023-05-25
- Granted: 2026-04-14
- Earliest claimed: 2021-11-23
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Michael Hell; Caspar Leendertz
- Web page: https://patentgrep.com/patent/US12604504B2

## CPC

- H10D 30/831: {Vertical FETs having PN junction gate electrodes (Vertical SIT H10D30/202)}
- H10D 62/8325: {Silicon carbide}
- H10D 12/441: {Vertical IGBTs}
- H10D 30/66: Vertical DMOS [VDMOS] FETs
- H10D 62/102: {Constructional design considerations for preventing surface leakage or controlling electric field concentration}
- H10D 62/107: {Buried supplementary regions, e.g. buried guard rings (multi-RESURF H10D62/111)}
- H10D 62/127: {of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs}
- H10D 62/393: {Body regions of DMOS transistors or IGBTs (cell layout of DMOS H10D62/127)}
- H10P 30/2042: {into crystalline silicon carbide}
- H10P 30/21: {of electrically active species}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A silicon carbide device includes: a planar gate structure on a first surface of a silicon carbide substrate, the planar gate structure having a gate length along a lateral first direction; a source region of a first conductivity type extending under the planar gate structure over at least part of the gate length; a body region of a second conductivity type, the body region including a channel zone that adjoins the source region under the planar gate structure; and a shielding region of the second conductivity type covering the channel zone over at least 20% but less than 100% of the gate length, wherein a maximum dopant concentration in the shielding region is higher than a maximum dopant concentration in the body region.

## Claims

### Claim 1

A silicon carbide device, comprising:
a planar gate structure on a first surface of a silicon carbide substrate, the planar gate structure having a gate length along a lateral first direction;
a source region of a first conductivity type extending under the planar gate structure over at least part of the gate length;
a body region of a second conductivity type, the body region including a channel zone that adjoins the source region under the planar gate structure; and
a shielding region of the second conductivity type covering the channel zone over at least part of the gate length,
wherein a maximum dopant concentration in the shielding region is higher than a maximum dopant concentration in the body region,
wherein the shielding region extends through the source region in a lateral second direction orthogonal to the lateral first direction, such that the source region is segmented into a plurality of sections that are separated from one another by the shielding region over at least part of the gate length.

### Claim 2 (depends on 1)

The silicon carbide device of claim 1, further comprising:
a body contact region of the second conductivity type adjoining both the body region and the source region at a side of the source region opposite the shielding region,
wherein a maximum dopant concentration in the body contact region is higher than a maximum dopant concentration in the body region,
wherein the shielding region merges with the body contact region between the sections of the source region.

### Claim 3 (depends on 1)

The silicon carbide device of claim 1, further comprising:
a current spreading region of the first conductivity type under the planar gate structure and adjoining a side of the channel zone opposite the source region, such that the channel zone is delimited on one side by the source region and on an opposite side by the current spreading region,
wherein the current spreading region extends from the first surface to a drift zone of the silicon carbide substrate,
wherein the drift zone extends under both the body region and the source region.

### Claim 4 (depends on 3)

The silicon carbide device of claim 3, wherein the shielding region extends through the current spreading region in a lateral second direction orthogonal to the lateral first direction.

### Claim 5 (depends on 3)

The silicon carbide device of claim 3, wherein the shielding region is delimited on one side by the source region and on an opposite side by the current spreading region.

### Claim 6 (depends on 1)

The silicon carbide device of claim 1, further comprising:
a buried shielding region of the second conductivity type under both the body region and the source region,
wherein a maximum dopant concentration in the buried shielding region is higher than the maximum dopant concentration in the body region,
wherein the shielding region and the buried shielding region vertically adjoin one another to provide shielding in each of the lateral first direction, a lateral second direction orthogonal to the lateral first direction, and a vertical direction orthogonal to both the lateral first direction and the lateral second direction.

### Claim 7 (depends on 1)

The silicon carbide device of claim 1, wherein the shielding region covers the channel zone over at least 30% but less than 100% of the gate length.

### Claim 8

A silicon carbide device, comprising:
a planar gate structure on a first surface of a silicon carbide substrate, the planar gate structure having a gate length along a lateral first direction;
a first source region of a first conductivity type extending under a first side of the planar gate structure over at least part of the gate length;
a first body region of a second conductivity type, the first body region including a channel zone that adjoins the first source region under the planar gate structure;
a second source region of the first conductivity type extending under a second side of the planar gate structure opposite the first side over at least part of the gate length;
a second body region of the second conductivity type, the second body region including a channel zone that adjoins the second source region under the planar gate structure;
a current spreading region of the first conductivity type separating the channel zone of the first body region and the channel zone of the second body region from one another under the planar gate structure; and
a shielding region of the second conductivity type covering both the channel zone of the first body region and the channel zone of the second body region over at least part of the gate length,
wherein the shielding region segments the channel zone of the first body region and the channel zone of the second body region into a plurality of sections below the planar gate structure.

### Claim 9 (depends on 8)

The silicon carbide device of claim 8, wherein the shielding region extends through both the first source region and the second source region in a lateral second direction orthogonal to the lateral first direction, such that the first source region and the second source region are each segmented into a plurality of sections that are separated from one another by the shielding region over at least part of the gate length.

### Claim 10 (depends on 9)

The silicon carbide device of claim 9, further comprising:
a first body contact region of the second conductivity type adjoining both the first body region and the first source region at a side of the first source region opposite the shielding region; and
a second body contact region of the second conductivity type adjoining both the second body region and the second source region at a side of the second source region opposite the shielding region,
wherein the shielding region merges with the first body contact region between the sections of the first source region,
wherein the shielding region merges with the second body contact region between the sections of the second source region.

### Claim 11 (depends on 10)

The silicon carbide device of claim 10, wherein the current spreading region separates the shielding region into a first section and a second section, wherein the first section of the shielding region extends from the current spreading region to the first body contact region in the lateral second direction, and wherein the second section of the shielding region extends from the current spreading region to the second body contact region in the lateral second direction.

### Claim 12 (depends on 10)

The silicon carbide device of claim 10, wherein the shielding region extends through the current spreading region in the lateral second direction, such that the shielding region extends uninterrupted between the first body contact region and the second body contact region in the lateral second direction.

### Claim 13 (depends on 8)

The silicon carbide device of claim 8, further comprising:
a first buried shielding region of the second conductivity type under both the first body region and the first source region; and
a second buried shielding region of the second conductivity type under both the second body region and the second source region,
wherein a maximum dopant concentration in the first buried shielding region is higher than the maximum dopant concentration in the first body region,
wherein a maximum dopant concentration in the second buried shielding region is higher than the maximum dopant concentration in the second body region,
wherein the shielding region and the first buried shielding region vertically adjoin one another to provide shielding in each of the lateral first direction, a lateral second direction orthogonal to the lateral first direction, and a vertical direction orthogonal to both the lateral first direction and the lateral second direction,
wherein the shielding region and the second buried shielding region vertically adjoin one another to provide shielding in each of the lateral first direction, the lateral second direction, and the vertical direction.

### Claim 14 (depends on 1)

The silicon carbide device of claim 1, wherein the shielding region covers both the channel zone of the first body region and the channel zone of the second body region over at least 20% but less than 100% of the gate length.

### Claim 15 (depends on 8)

The silicon carbide device of claim 8, wherein the shielding region covers both the channel zone of the first body region and the channel zone of the second body region over at least 20% but less than 100% of the gate length.

### Claim 16

A silicon carbide device, comprising:
a planar gate structure on a first surface of a silicon carbide substrate, the planar gate structure having a gate length along a lateral first direction;
a source region of a first conductivity type extending under the planar gate structure over at least part of the gate length;
a body region of a second conductivity type, the body region including a channel zone that adjoins the source region under the planar gate structure; and
a shielding region of the second conductivity type covering the channel zone over at least part of the gate length,
wherein a maximum dopant concentration in the shielding region is higher than a maximum dopant concentration in the body region,
wherein under the planar gate structure, the shielding region extends to the first surface of the silicon carbide substrate in a vertical direction that is orthogonal to the lateral first direction.

### Claim 17 (depends on 16)

The silicon carbide device of claim 16, wherein the source region is uninterrupted by the shielding region over the gate length, such that the shielding region is delimited on one side by the source region.

### Claim 18 (depends on 16)

The silicon carbide device of claim 16, further comprising:
a current spreading region of the first conductivity type under the planar gate structure and adjoining a side of the channel zone opposite the source region, such that the channel zone is delimited on one side by the source region and on an opposite side by the current spreading region,
wherein the current spreading region extends from the first surface to a drift zone of the silicon carbide substrate,
wherein the drift zone extends under both the body region and the source region.

### Claim 19 (depends on 18)

The silicon carbide device of claim 18, wherein the shielding region is delimited on one side by the source region and on an opposite side by the current spreading region.

### Claim 20 (depends on 18)

The silicon carbide device of claim 18, wherein the current spreading region separates the shielding region into a first section and a second section.

### Claim 21 (depends on 16)

The silicon carbide device of claim 16, further comprising:
a body contact region of the second conductivity type adjoining both the body region and the source region,
wherein a maximum dopant concentration in the body contact region is higher than a maximum dopant concentration in the body region,
wherein the shielding region merges with the body contact region in an area where the shielding region extends to the first surface of the silicon carbide substrate.

### Claim 22 (depends on 21)

The silicon carbide device of claim 21, wherein no distinguishable interface is present where the shielding region merges with the body contact region.