Crystal growth apparatus and manufacturing method of group III nitride crystal

Patent metadata

Field	Value
Publication number	US-9856575-B2
Application number	US-201514853133-A
Country	US
Kind code	B2
Filing date	Sep 14, 2015
Priority date	Oct 14, 2005
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A crystal growth apparatus comprises a reaction vessel holding a melt mixture containing an alkali metal and a group III metal, a gas supplying apparatus supplying a nitrogen source gas to a vessel space exposed to the melt mixture inside the reaction vessel, a heating unit heating the melt mixture to a crystal growth temperature, and a support unit supporting a seed crystal of a group III nitride crystal inside the melt mixture.

First claim

What is claimed is:

1. A method of manufacturing a group III nitride crystal, comprising the steps of:
loading an alkali metal and a group III metal into a reaction vessel;
introducing a nitrogen source gas into the reaction vessel;
heating the reaction vessel to form a melt mixture of the alkali metal and the group III metal in the reaction vessel;
detecting an integrated flow rate of the nitrogen source gas, and judging whether supersaturation is attained for a concentration of nitrogen or a concentration of a group III nitride in the melt mixture, based on the integrated flow rate;
moving, after supersaturation is attained for the concentration of nitrogen or the concentration of a group III nitride in the melt mixture, at least a part of a seed crystal so as to make a contact with the melt mixture; and
growing a group III nitride crystal upon the seed crystal in the reaction vessel.

2. The method as claimed in claim 1 , further comprising detecting the concentration of nitrogen or the concentration of the group III nitride in the melt mixture.

3. The method as claimed in claim 1 , further comprising detecting a temperature of the melt mixture.

4. The method as claimed in claim 3 , further comprising obtaining a solubility of nitrogen or the group III nitride in the melt mixture for the detected temperature, wherein it is judged that the supersaturation is attained for the concentration of nitrogen or for the concentration of the group III nitride when the integrated flow rate detected for the nitrogen source gas is larger than an integrated flow rate of the nitrogen source gas corresponding to the detected solubility.

5. The method as claimed in claim 1 , wherein the seed crystal is held at a temperature lower than a temperature of the melt mixture.

6. The method as claimed in claim 5 , wherein the seed crystal is held at the temperature lower than the temperature of the melt mixture by cooling.

7. The method as claimed in claim 1 , wherein the seed crystal is moved from an upward position relative to a vapor-liquid interface of the melt mixture and a vapor to a position where the at least a part of the seed crystal makes a contact with the melt mixture.

8. The method as claimed in claim 1 , wherein the seed crystal is moved from a position immersed in the melt mixture to the position in which at least a part of the seed crystal makes a contact with the melt mixture.

9. The method as claimed in claim 1 , wherein the moving comprises applying a vibration to a support unit supporting the seed crystal and detecting a vibrational signal indicative of vibration of the support unit, and moving the support unit such that the detected vibration signal becomes a vibration signal for a case in which the seed crystal is contacted with the melt mixture.

10. The method as claimed in claim 1 , wherein the seed crystal is moved during the growing such that a grown group III nitride crystal makes a contact with the melt mixture.

Assignees

• Sarayama Seiji
• Iwata Hirokazu
• Fuse Akihiro
• Ricoh Co Ltd

Inventors

• Sarayama Seiji
• Iwata Hirokazu
• Fuse Akihiro

Classifications

• C30B9/10 Primary

  Metal solvents · CPC title

• C30B29/40

  AIIIBV compounds {wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi} · CPC title

• C30B17/00

  Single-crystal growth onto a seed which remains in the melt during growth, e.g. Nacken-Kyropoulos method (C30B15/00 takes precedence) · CPC title

• Y10T117/1092

  Shape defined by a solid member other than seed or product [e.g., Bridgman-Stockbarger] · CPC title

• C30B9/00

  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 title