Single-crystal silicon carbide and single-crystal silicon carbide wafer

Patent metadata

Field	Value
Publication number	US-9777403-B2
Application number	US-99835709-A
Country	US
Kind code	B2
Filing date	Oct 14, 2009
Priority date	Oct 15, 2008
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A single-crystal silicon carbide and a single-crystal silicon carbide wafer of good-quality are disclosed that are low in dislocations, micropipes and other crystal defects and enable high yield and high performance when applied to a device, wherein the ratio of doping element concentrations on opposite sides in the direction of crystal growth of the interface between the seed crystal and the grown crystal is 5 or less and the doping element concentration of the grown crystal in the vicinity of the seed crystal is 2×10 19 cm −3 to 6×10 20 cm −3 .

First claim

What is claimed is:

1. A single-crystal silicon carbide manufactured by the modified Lely process, comprising:
a seed crystal, wherein nitrogen concentration of the seed crystal is greater than 1×10 19 cm −3 ; and
a grown crystal grown on the seed crystal, wherein doping element concentration of the grown crystal at least in a region in the vicinity of the seed crystal is 2×10 19 cm −3 to 6×10 20 cm −3 and a ratio of higher to lower doping element concentrations on opposite sides of an interface between the seed crystal and the grown crystal (concentration of high concentration side crystal/concentration of low concentration side crystal) is from 1.05 to 5.

2. A single-crystal silicon carbide according to claim 1 , wherein the region in the vicinity of the seed crystal is a region of 0.5 mm or less thickness on the grown crystal side of the interface between the seed crystal and the grown crystal.

3. A single-crystal silicon carbide according to claim 1 , wherein the ratio of higher to lower doping element concentrations is from 1.05 to 2.

4. A single-crystal silicon carbide according to claim 1 , wherein the ratio of higher to lower doping element concentrations is from 1.05 to 1.5.

5. A single-crystal silicon carbide according to claim 1 , wherein the doping element concentration of the grown crystal in a region in the vicinity of the seed crystal is 5×10 19 cm −3 to 6×10 20 cm −3 .

6. A single-crystal silicon carbide according to claim 1 , wherein the doping element concentration of the grown crystal in a region in the vicinity of the seed crystal is 1×10 20 cm −3 to 6×10 20 cm −3 .

7. A single-crystal silicon carbide according to claim 1 , wherein the doping element is nitrogen.

8. A single-crystal silicon carbide according to claim 1 , wherein the principal polytype is 4H.

9. A single-crystal silicon carbide according to claim 1 , wherein total etch pit density caused by all types of dislocation observed in a wafer of an off-angle of 8° from the {0001} plane made from grown crystal excluding a region in the vicinity of the seed crystal is 1×10 4 cm −2 or less and the micropipe density observed therein is 10 cm −2 or less.

10. A single-crystal silicon carbide according to claim 1 , wherein total etch pit density caused by all types of dislocation observed in a wafer of an off-angle of 8° from the {0001} plane made from grown crystal excluding a region in the vicinity of the seed crystal is 5×10 3 cm −2 or less and the micropipe density observed therein is 5 cm −2 or less.

11. A single-crystal silicon carbide wafer made from grown crystal excluding a region in the vicinity of the seed crystal of the single-crystal silicon carbide according to claim 1 , whose diameter is 75 mm to 300 mm and polytype other than in the edge exclusion region is 4H.

Assignees

• Nakabayashi Masashi
• Fujimoto Tatsuo
• Katsuno Masakazu
• Tsuge Hiroshi
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Nakabayashi Masashi
• Fujimoto Tatsuo
• Katsuno Masakazu
• Tsuge Hiroshi

Classifications

• H10P95/00 Primary

  Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass · CPC title

• C30B23/025

  characterised by the substrate · CPC title

• C30B25/00

  Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth · CPC title

• Y10T428/2918

  including free carbon or carbide or therewith [not as steel] · CPC title

• C30B29/36 Primary

  Carbides · CPC title