Method of producing crystal

Patent metadata

Field	Value
Publication number	US-10443149-B2
Application number	US-201515114751-A
Country	US
Kind code	B2
Filing date	Jan 29, 2015
Priority date	Jan 29, 2014
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

A method of producing a crystal includes a step of preparing a solution containing carbon and a silicon solvent, and a seed crystal of silicon carbide; a step of contacting a lower face of the seed crystal with the solution; a step of raising a temperature of the solution to a first temperature zone; a step of relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to a second temperature zone; a step of raising a temperature of the solution from the second temperature zone to the first temperature zone; and a step of relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to the second temperature zone.

First claim

The invention claimed is:

1. A method of producing a crystal, in the method a silicon carbide crystal being grown on a lower face of a seed crystal of silicon carbide by a solution technique, the method comprising:
a preparation step of preparing a solution obtained by dissolving carbon in a silicon solvent, and a seed crystal of silicon carbide;
a contact step of bringing a lower face of the seed crystal into contact with the solution;
a crystal growth initiation step of raising a temperature of the solution to a first temperature zone within a temperature range where the silicon solvent remains liquefied and thereby initiating growth of silicon carbide crystal on the lower face of the seed crystal;
a first crystal growth step of, after the crystal growth initiation step, relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to a second temperature zone within a temperature range where the silicon solvent remains liquefied, and thereby growing the silicon carbide crystal;
a solution temperature raising step of, after the first crystal growth step, raising a temperature of the solution from the second temperature zone to the first temperature zone while increasing a gas supply rate to the growth atmosphere of the crystal; and
a second crystal growth step of, after the solution temperature raising step, relatively elevating the seed crystal with respect to the solution in a state where a temperature of the solution is being lowered from the first temperature zone to the second temperature zone and thereby achieving subsequent growth of the silicon carbide crystal,
wherein the crystal is separated from the solution between the first crystal growth step and the solution temperature raising step, and then the crystal is brought into contact with the solution before the second crystal growth step, and
wherein at the solution temperature raising step, the solution is raised to the first temperature zone after a silicon material added to the solution.

2. The method according to claim 1 , wherein the solution temperature raising step and the second crystal growth step are both repeated plural times.

3. The method according to claim 1 , wherein a temperature of the solution in the first temperature zone of the solution temperature raising step is higher than or equal to a temperature of the solution in the first temperature zone of the first crystal growth step.

4. The method according to claim 1 , wherein a time of raising a temperature of the solution from the second temperature zone to the first temperature zone at the solution temperature raising step is shorter than a time of lowering a temperature of the solution from the first temperature zone to the second temperature zone at the first crystal growth step and the second crystal growth step.

5. The method according to claim 1 , wherein the contact step is performed before a temperature of the solution is raised to the first temperature zone at the crystal growth initiation step.

6. The method according to claim 1 , wherein the crystal is separated from the solution in a state where the crystal is rotated together with the seed crystal.

7. The method according to claim 1 , wherein the crystal is brought into contact with the solution in the solution temperature raising step.

8. The method according to claim 1 , wherein the solution is contained in a crucible containing carbon after the preparation step.

9. The method according to claim 1 , further comprising a solution temperature maintaining step of maintaining a temperature of the solution within the first temperature zone for a predetermined time, after the crystal growth initiation step.

10. The method according to claim 1 , wherein the solution temperature maintaining step is performed between the solution temperature raising step and the second crystal growth step.

11. The method according to claim 1 , wherein in the solution temperature raising step, the lower face of the crystal is again brought into contact with the solution in a state where a temperature of the solution is maintained at constant for a predetermined time.

Assignees

• Kyocera Corp

Inventors

• Domoto Chiaki
• Kuba Yutaka
• Masaki Katsuaki
• Hayashi Yuuichiro

Classifications

• C30B19/10 Primary

  Controlling or regulating (controlling or regulating in general G05) · CPC title

• C30B15/14

  Heating of the melt or the crystallised materials · CPC title

• C30B9/06

  using as solvent a component of the crystal composition · CPC title

• C30B19/062

  Vertical dipping system · CPC title

• C30B29/36

  Carbides · CPC title