# US 10,121,865 B2 · Silicon carbide epitaxial substrate and method of manufacturing silicon carbide semiconductor device

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- Number: US 10,121,865 B2
- Document ID: US10121865B2
- Status: Granted
- Kind: B2
- Application number: 15/319,130
- Filed: 2016-07-04
- Published: 2017-10-05
- Granted: 2018-11-06
- Earliest claimed: 2015-09-11
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Industries, Ltd.
- Inventors: Tsutomu Hori; Hironori Itoh
- Web page: https://patentgrep.com/patent/US10121865B2

## CPC

- H10D 62/60: Impurity distributions or concentrations
- C23C 16/4584: {the substrate being rotated}
- C23C 16/52: Controlling or regulating the coating process {(C23C16/45557, C23C16/279 take precedence)}
- C30B 25/165: {the flow of the reactive gases}
- C30B 25/20: the substrate being of the same materials as the epitaxial layer
- C30B 29/36: Carbides
- H10D 12/031: {of IGBTs}
- H10D 30/0291: {of vertical DMOS [VDMOS] FETs}
- H10D 62/8325: {Silicon carbide}
- H10D 64/0115: {to silicon carbide}
- H10D 64/01366: {the semiconductor being silicon carbide}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2904: {Silicon carbide}
- H10P 14/2926: {Crystal orientations}
- H10P 14/3208: {Silicon carbide}
- H10P 14/3216: {Nitrides}
- H10P 14/3408: {Silicon carbide}
- H10P 14/3442: {N-type}
- H10P 14/3466: {Crystal orientation}
- H10P 30/2042: {into crystalline silicon carbide}
- H10P 30/21: {of electrically active species}
- H10P 54/00: Cutting or separating of wafers, substrates or parts of devices
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The silicon carbide layer has a second main surface. The second main surface has a peripheral region within 5 mm from an outer edge thereof, and a central region surrounded by the peripheral region. The silicon carbide layer has a central surface layer. An average value of a carrier concentration in the central surface layer is not less than 1×1014 cm−3 and not more than 5×1016 cm−3. Circumferential uniformity of the carrier concentration is not more than 2%, and in-plane uniformity of the carrier concentration is not more than 10%. An average value of a thickness of a portion of the silicon carbide layer sandwiched between the central region and the silicon carbide single-crystal substrate is not less than 5 μm. Circumferential uniformity of the thickness is not more than 1%, and in-plane uniformity of the thickness is not more than 4%.

## Claims

### Claim 1

A silicon carbide epitaxial substrate comprising:
a silicon carbide single-crystal substrate having a first main surface; and
a silicon carbide layer on the first main surface,
the silicon carbide layer having a second main surface opposite to a surface thereof in contact with the silicon carbide single-crystal substrate,
the second main surface having a maximum diameter of not less than 100 mm,
the second main surface having a peripheral region within 5 mm from an outer edge of the second main surface, and a central region surrounded by the peripheral region,
the silicon carbide layer having a central surface layer including the central region,
an average value of a carrier concentration in the central surface layer being not less than 1×1014 cm−3 and not more than 5×1016 cm−3,
circumferential uniformity of the carrier concentration being not more than 2%, and in-plane uniformity of the carrier concentration being not more than 10%,
an average value of a thickness of a portion of the silicon carbide layer sandwiched between the central region and the silicon carbide single-crystal substrate being not less than 5 μm,
circumferential uniformity of the thickness being not more than 1%, and in-plane uniformity of the thickness being not more than 4%,
the circumferential uniformity of the carrier concentration being a ratio of an absolute value of a difference between a maximum value and a minimum value of the carrier concentration in the central surface layer in a circumferential direction, to an average value of the carrier concentration in the central surface layer in the circumferential direction,
the in-plane uniformity of the carrier concentration being a ratio of an absolute value of a difference between a maximum value and a minimum value of the carrier concentration in the central surface layer in the entire central region, to an average value of the carrier concentration in the central surface layer in the entire central region,
the circumferential uniformity of the thickness being a ratio of an absolute value of a difference between a maximum value and a minimum value of the thickness of the portion in the circumferential direction, to an average value of the thickness of the portion in the circumferential direction,
the in-plane uniformity of the thickness being a ratio of an absolute value of a difference between a maximum value and a minimum value of the thickness of the portion in the entire central region, to an average value of the thickness of the portion in the entire central region.

### Claim 2 (depends on 1)

The silicon carbide epitaxial substrate according to claim 1, wherein
the maximum diameter is not less than 150 mm.

### Claim 3 (depends on 1)

The silicon carbide epitaxial substrate according to claim 1, wherein
the average value of the carrier concentration is not less than 1×1015 cm−3 and not more than 1×1016 cm−3.

### Claim 4 (depends on 1)

The silicon carbide epitaxial substrate according to claim 1, wherein
the circumferential uniformity of the carrier concentration is not more than 1%.

### Claim 5 (depends on 1)

The silicon carbide epitaxial substrate according to claim 1, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 6 (depends on 1)

A method of manufacturing a silicon carbide semiconductor device, comprising the steps of:
preparing the silicon carbide epitaxial substrate according to claim 1; and
processing the silicon carbide epitaxial substrate.

### Claim 7 (depends on 2)

The silicon carbide epitaxial substrate according to claim 2, wherein
the average value of the carrier concentration is not less than 1×1015 cm−3 and not more than 1×1016 cm−3.

### Claim 8 (depends on 2)

The silicon carbide epitaxial substrate according to claim 2, wherein
the circumferential uniformity of the carrier concentration is not more than 1%.

### Claim 9 (depends on 3)

The silicon carbide epitaxial substrate according to claim 3, wherein
the circumferential uniformity of the carrier concentration is not more than 1%.

### Claim 10 (depends on 7)

The silicon carbide epitaxial substrate according to claim 7, wherein
the circumferential uniformity of the carrier concentration is not more than 1%.

### Claim 11 (depends on 2)

The silicon carbide epitaxial substrate according to claim 2, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 12 (depends on 3)

The silicon carbide epitaxial substrate according to claim 3, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 13 (depends on 4)

The silicon carbide epitaxial substrate according to claim 4, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 14 (depends on 7)

The silicon carbide epitaxial substrate according to claim 7, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 15 (depends on 8)

The silicon carbide epitaxial substrate according to claim 8, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 16 (depends on 9)

The silicon carbide epitaxial substrate according to claim 9, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.

### Claim 17 (depends on 10)

The silicon carbide epitaxial substrate according to claim 10, wherein
the in-plane uniformity of the carrier concentration is not more than 5%.