# US 2023/0053501 A1 · Silicon carbide semiconductor device and power conversion apparatus

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- Number: US 2023/0053501 A1
- Document ID: US20230053501A1
- Status: Published application
- Kind: A1
- Application number: 17/852,284
- Filed: 2022-06-28
- Published: 2023-02-23
- Earliest claimed: 2021-08-17
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Katsuhiro FUJIYOSHI; Toshikazu TANIOKA
- Web page: https://patentgrep.com/patent/US20230053501A1

## CPC

- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H10D 30/665: {having edge termination structures}
- H02M 7/003: {Constructional details, e.g. physical layout, assembly, wiring or busbar connections}
- H02M 7/53871: {with automatic control of output voltage or current}
- H10D 62/106: {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}
- H10D 62/8325: {Silicon carbide}
- H10D 64/111: {Field plates}
- H10W 42/00: Arrangements for protection of devices (arrangements for thermal protection H10W40/00)
- H10W 74/137: {the encapsulations being directly on the semiconductor body (H10W74/134 takes precedence)}
- H02M 7/537: using semiconductor devices only, e.g. single switched pulse inverters
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A silicon carbide semiconductor device includes an n-type epitaxial layer provided on a SiC substrate, a front surface electrode provided on the epitaxial layer, and a p-type electric field relieving region provided in the upper layer of the epitaxial layer in a terminal region. On the epitaxial layer, a first protective film composed of an interlayer insulating film and a protective oxide film that covers at least a part of the electric field relieving region is provided. A second protective film composed of a polyimide protective film is provided via a silicon nitride film so as to cover the outer end portion of the surface electrode, the first protective film, and at least a part of the epitaxial layer. The silicon nitride film protrudes from the second protective film at both an inner side end portion and an outer side end portion.

## Claims

### Claim 1

A silicon carbide semiconductor device comprising:
a semiconductor substrate composed of silicon carbide;
a semiconductor layer of first conductivity type provided on the semiconductor substrate;
a first main electrode provided on the semiconductor layer;
a second main electrode provided on a back surface of the semiconductor substrate;
an electric field relieving region of second conductivity type provided in an upper layer of the semiconductor layer in a terminal region outside an element region in which the main current flows;
a first protective film provided on the semiconductor layer and covering at least a part of the electric field relieving region;
a silicon nitride film covering an outer end portion of the first main electrode, the first protective film, and at least a part of the semiconductor layer outside the first protective film; and
a second protective film provided on the silicon nitride film, wherein
the silicon nitride film protrudes from the second protective film at both an inner side end portion and an outer side end portion.

### Claim 2 (depends on 1)

The silicon carbide semiconductor device according to claim 1, wherein
a protruding length the silicon nitride film protrudes from the inner side end portion of the second protective film is shorter than a protruding length the silicon nitride film protrudes from the outer side end portion of the second protective film.

### Claim 3 (depends on 1)

The silicon carbide semiconductor device according to claim 1, wherein
the silicon nitride film extends to a chip end portion of the silicon carbide semiconductor device.

### Claim 4 (depends on 1)

The silicon carbide semiconductor device according to claim 1, wherein
a side surface of the end portion of the first main electrode covered with the silicon nitride film is inclined.

### Claim 5 (depends on 1)

The silicon carbide semiconductor device according to claim 1, further comprising
a frame electrode covering an outer end portion of the first protective film and having a stair-shape having a step that fits the outer end portion of the first protective film, wherein
the silicon nitride film covers the frame electrode.

### Claim 6 (depends on 1)

A power conversion apparatus comprising:
a main conversion circuit configured to convert power to be input and output thereof, the main conversion circuit having the silicon carbide semiconductor device according to claim 1; and
a control circuit configured to output a control signal for controlling the main conversion circuit to the main conversion circuit.