Method for producing silicon carbide (SiC) single crystal and silicon carbide (SiC) single crystal obtained by such method

• US 7,419,545 B2
• Filed: 12/26/2005
• Issued: 09/02/2008
• Est. Priority Date: 12/28/2004
• Status: Expired due to Fees

• Current Assignee: Osaka University, Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Osaka University, Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kawamura, Fumio, Mori, Yusuke, Sasaki, Takatomo, Kawahara, Minoru, Kitaoka, Yasuo
• Primary Examiner(s): HITESHEW, FELISA CARLA
• Application Number:
  US10/599,035
• Publication Number:
  US 20070221122A1
• Time in Patent Office: 981 Days
• Field of Search: 233/01.R, 117/68, 117/71, 117/79, 117/109, 117/951, 117/952, 117/13, 117/15, 117/217, 117/218, 117/222, 252/62.3 C
• US Class Current: 117/15
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 9/00 Single-crystal growth from melt solutions using molten solvents by normal or gradient freezing C30B11/00; by zone-melting C30B13/00; by crystal pulling C30B15/00; on immersed seed crystal C30B17/00; by liquid phase epitaxial growth C30B19/00; under a protective fluid C30B27/00
• CPC Class Codes: C30B 9/10 Metal solvents
• CPC Class Codes: Y10T 117/1068 including heating or cooling details [e.g., shield configuration]
• CPC Class Codes: Y10T 117/1072 including details of means providing product movement [e.g., shaft guides, servo means]
• CPC Class Codes: Y10T 117/1088 including heating or cooling details

Abstract

The present invention provides a producing method with which large silicon carbide (SiC) single crystal can be produced at low cost. Silicon carbide single crystal is produced or grown by dissolving and reacting silicon (Si) and carbon (C) in an alkali metal flux. The alkali metal preferably is lithium (Li). With this method, silicon carbide single crystal can be produced even under low-temperature conditions of 1500° C. or lower, for example. The photograph of FIG. 3B is an example of a silicon carbide single crystal obtained by the method of the present invention.

Claims

1. A method for producing a silicon carbide (SiC) single crystal, wherein a simple substance of silicon (Si) and carbon (C) are heated at 1000°

C. or lower, and are dissolved in an alkali metal flux, and are reacted to produce or grow the silicon carbide single crystal.

2. The producing method according to claim 1, wherein the silicon carbide single crystal is a 2H—

SiC single crystal or a 3C—

SiC single crystal.

3. The producing method according to claim 1, wherein the silicon carbide single crystal is produced or grown by cooling the alkali metal flux in which the silicon and the carbon are dissolved.

4. The producing method according to claim 3, wherein the silicon and the carbon are dissolved in the alkali metal flux by heating the silicon, the carbon, and the alkali metal, and the heated state is maintained for a specific length of time, and then the heating temperature is lowered to cool the alkali metal flux.

5. The producing method according to claim 1, wherein a temperature gradient is formed in the alkali metal flux, the silicon and the carbon are dissolved in a high-temperature region of the temperature gradient, and the silicon carbide single crystal is produced or grown in a low-temperature region of the temperature gradient.

6. The producing method according to claim 1, wherein the alkali metal is at least one selected from the group consisting of lithium (Li), sodium (Na), and potassium (K).

7. The producing method according to claim 1, wherein the alkali metal is lithium (Li).

8. The producing method according to claim 1, wherein the alkali metal flux further includes an alkaline earth metal.

9. The producing method according to claim 1, wherein the reaction is conducted in a reaction vessel, and the carbon is supplied from a material from which the reaction vessel is formed.

10. The producing method according to claim 9, wherein the reaction vessel is formed from a carbon-based material.

11. The producing method according to claim 10, wherein the carbon-based material is graphite.

12. The producing method according to claim 1, wherein a silicon carbide crystal is produced beforehand as a seed crystal, and the seed crystal is used as a nucleus to grow new silicon abide single crystal.

13. The producing method according to claim 1, wherein the silicon carbide single crystal is produced or grown under a pressurized atmosphere.

14. The producing method according to claim 1, wherein the silicon carbide single crystal is produced or grown under an inert gas atmosphere.

15. The producing method according to claim 14, wherein the inert gas is at least one of argon (Ar) gas and a hydrocarbon gas.

16. The producing method according to claim 15, wherein the hydrocarbon gas is at least one of methane gas and propane gas.

17. The producing method according to claim 1, wherein the alkali metal flux further includes an impurity as dopant.

18. The producing method according to claim 1, wherein the silicon carbide single crystal is a 2H—

SiC single crystal.