Silicon carbide epitaxial substrate

Patent metadata

Field	Value
Publication number	US-2018233562-A1
Application number	US-201515516148-A
Country	US
Kind code	A1
Filing date	Aug 18, 2015
Priority date	Oct 1, 2014
Publication date	Aug 16, 2018
Grant date	—

Abstract

A silicon carbide epitaxial substrate includes: a silicon carbide single crystal substrate; and an epitaxial layer. The silicon carbide single crystal substrate has a diameter of not less than 100 mm. The epitaxial layer has a thickness of not less than 10 μm. The epitaxial layer has a carrier concentration of not less than 1×1014 cm−3 and not more than 1×1016 cm−3. A ratio of a standard deviation of the carrier concentration in a plane of the epitaxial layer to an average value of the carrier concentration in the plane is not more than 10%. The epitaxial layer has a main surface. The main surface has an arithmetic mean roughness Sa of not more than 0.3 nm. An area density of pits originated from a threading screw dislocation is not more than 1000 cm−2. Each of the pits has a maximum depth of not less than 8 nm.

First claim

1 . A silicon carbide epitaxial substrate comprising:
a silicon carbide single crystal substrate; and an epitaxial layer on the silicon carbide single crystal substrate, the silicon carbide single crystal substrate having a diameter of not less than 100 mm, the epitaxial layer having a thickness of not less than 10 μm, the epitaxial layer having a carrier concentration of not less than 1×10 14 cm −3 and not more than 1×10 16 cm −3 , a ratio of a standard deviation of the carrier concentration in a plane of the epitaxial layer to an average value of the carrier concentration in the plane being not more than 10%, the epitaxial layer having a main surface, the main surface having an arithmetic mean roughness Sa of not more than 0.3 nm in three-dimensional surface roughness measurement, an area density of pits originated from a threading screw dislocation being not more than 1000 cm −2 in the main surface, each of the pits having a maximum depth of not less than 8 nm from the main surface.

2 . The silicon carbide epitaxial substrate according to claim 1 , wherein the area density is not more than 100 cm −2 .

3 . The silicon carbide epitaxial substrate according to claim 1 , wherein the area density is not more than 10 cm −2 .

4 . The silicon carbide epitaxial substrate according to claim 1 , wherein the area density is not more than 1 cm −2 .

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

6 . The silicon carbide epitaxial substrate according to claim 1 , wherein the diameter is not less than 200 mm.

7 . The silicon carbide epitaxial substrate according to claim 1 , wherein the ratio is not more than 5%.

8 . The silicon carbide epitaxial substrate according to claim 1 , wherein the maximum depth is not less than 20 nm.

9 . The silicon carbide epitaxial substrate according to claim 1 , wherein
each of the pits has a planar shape including a first width and a second width, the first width extending in a first direction, the second width extending in a second direction perpendicular to the first direction, and the first width is twice or more as large as the second width.

10 . A silicon carbide epitaxial substrate comprising:
a silicon carbide single crystal substrate; and an epitaxial layer on the silicon carbide single crystal substrate, the silicon carbide single crystal substrate having a diameter of not less than 100 mm, the epitaxial layer having a thickness of not less than 10 μm, the epitaxial layer having a carrier concentration of not less than 1×10 14 cm −3 and not more than 1×10 16 cm −3 , a ratio of a standard deviation of the carrier concentration in a plane of the epitaxial layer to an average value of the carrier concentration in the plane being not more than 10%, the epitaxial layer having a main surface, the main surface having an arithmetic mean roughness Sa of not more than 0.3 nm in three-dimensional surface roughness measurement, an area density of pits originated from a threading screw dislocation being not more than 1000 cm −2 in the main surface, each of the pits having a planar shape including a first width and a second width, the first width extending in a first direction, the second width extending in a second direction perpendicular to the first direction, the first width being twice or more as large as the second width, each of the pits having a maximum depth of not less than 20 nm from the main surface.

Assignees

• Sumitomo Electric Industries

Inventors

• Nishiguchi Taro
• Wada Keiji
• Genba Jun
• Itoh Hironori
• Doi Hideyuki
• Hiratsuka Kenji

Classifications

• H10P14/3442

  N-type · CPC title

• H10P14/3408

  Silicon carbide · CPC title

• H10P14/3208

  Silicon carbide · CPC title

• H10P14/2926

  Crystal orientations · CPC title

• H10P14/2904

  Silicon carbide · CPC title