Method for producing group-III nitride crystal, group-III nitride crystal, semiconductor device, and device for producing group-III nitride crystal

Patent metadata

Field	Value
Publication number	US-10266965-B2
Application number	US-201515123556-A
Country	US
Kind code	B2
Filing date	Feb 26, 2015
Priority date	Mar 3, 2014
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A large Group III nitride crystal of high quality with few defects such as a distortion, a dislocation, and warping is produced by vapor phase epitaxy. A method for producing a Group III nitride crystal includes: a first Group III nitride crystal production process of producing a first Group III nitride crystal 1003 by liquid phase epitaxy; and a second Group III nitride crystal production process of producing a second Group III nitride crystal 1004 on the first crystal 1003 by vapor phase epitaxy. In the first Group III nitride crystal production process, the surfaces of seed crystals 1003 a (preliminarily provided Group III nitride) are brought into contact with an alkali metal melt, a Group III element and nitrogen are cause to react with each other in a nitrogen-containing atmosphere in the alkali metal melt, and the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals 1003 a to produce a first crystal 1003.

First claim

The invention claimed is:

1. A method for producing a Group III nitride crystal, comprising:
a first Group III nitride crystal production process of producing a first Group III nitride crystal by liquid phase epitaxy; and
a second Group III nitride crystal production process of producing a second Group III nitride crystal on the first Group III nitride crystal by vapor phase epitaxy,
the first Group III nitride crystal production process comprising:
a seed crystal selection step of selecting a plurality of parts of a preliminarily provided Group III nitride as seed crystals for generation and growth of Group III nitride crystals;
a contact step of bringing the surfaces of the seed crystals into contact with an alkali metal melt; and
a Group III nitride crystal liquid phase growth step of causing a Group III element and nitrogen to react with each other in a nitrogen-containing atmosphere in the alkali metal melt to generate and grow Group III nitride crystals,

wherein in the Group III nitride crystal liquid phase growth step, the Group III nitride crystals are bound together by growth of the Group III nitride crystals grown from the seed crystals to produce the first Group III nitride crystal,
in the Group III nitride crystal liquid phase growth step, the first Group III nitride crystal includes at least one of (a) through holes obtained by not binding some parts of Group III nitride crystals that are adjacent to one another, and (b) concave portions, and
in the second Group III nitride crystal production process, the second Group III nitride crystal is grown so as to fill or cover the through holes or the concave portions that remain in the first Group III nitride crystal with the second Group III nitride crystal.

2. The method according to claim 1 , wherein
the first Group III nitride crystal has substantially no polarity inversion region.

3. The method according to claim 1 , wherein
the second Group III nitride crystal produced in the second Group III nitride crystal production process has substantially no polarity inversion region.

4. The method according to claim 1 , wherein
in the first Group III nitride crystal production process, the seed crystals are hexagonal crystals, and
in the seed crystal selection step, the seed crystals are arranged such that m-planes of the crystals grown from the seed crystals that are adjacent to each other do not almost coincide with each other.

5. The method according to claim 4 , wherein
the seed crystals are arranged such that a-axes or c-axes of the seed crystals that are adjacent to each other almost coincide with each other.

6. The method according to claim 4 , wherein
each seed crystal has a c-plane, and
in the seed crystal selection step, the c-planes are selected as crystal growth planes of the seed crystals, and
the seed crystals are arranged such that a-axes of the seed crystals that are adjacent to each other almost coincide with each other.

7. The method according to claim 6 , wherein
in the Group III nitride crystal liquid phase growth step, the seed crystals are arranged such that apexes of hexagons of the Group III nitride crystals grown from the seed crystals that are adjacent to each other almost coincide with each other.

8. The method according to claim 4 , wherein
the seed crystals are arranged such that the sides of the crystals grown from the seed crystals do not almost coincide with each other.

9. The method according to claim 1 , wherein
in the seed crystal selection step,
the preliminarily provided Group III nitride includes a plurality of Group III nitride crystals arranged on a substrate, and
the Group III nitride crystals are selected as the seed crystals, or
in the seed crystal selection step,
the preliminarily provided Group III nitride is a Group III nitride crystal layer, a mask having a plurality of through holes is arranged on the Group III nitride crystal layer, and parts of the plane the Group III nitride crystal layer exposed from the through holes are selected as the seed crystals.

10. The method according to claim 9 , wherein
in the seed crystal selection step,
the preliminarily provided Group III nitride includes a plurality of Group III nitride crystals arranged on a substrate, the Group III nitride crystals are selected as the seed crystals, and the Group III nitride crystals arranged on the substrate are Group III nitride crystals formed by removing parts of the Group III nitride crystal layer formed on the substrate.

11. The method according to claim 9 , wherein
in the seed crystal selection step,
the preliminarily provided Group III nitride is a Group III nitride crystal layer, a mask having a plurality of through holes is arranged on the Group III nitride crystal layer, parts of the plane of the Group III nitride crystal layer exposed from the through holes are selected as the seed crystals, and the mask does not adhere to the Group III nitride crystal layer.

12. The method according to claim 9 , wherein
in the seed crystal selection step, the contact step, and the crystal growth step, a plurality of units each composed of the Group III nitride crystal layer and the mask or a plurality of units each composed of the substrate and the Group III nitride crystal are adjacently arranged in parallel, and
in the crystal growth step, the Group III nitride crystals grown from the units that are adjacent to each other are bound together by the growth of the Group III nitride crystals.

13. The method according to claim 12 , wherein
in the first Group III nitride crystal production process, the seed crystals are hexagonal crystals, and
the seed crystals are arranged such that m-planes of the crystals grown from the seed crystals that are adjacent to each other do not almost coincide with each other between the units that are adjacent to each other.

14. The method according to claim 13 , wherein
the seed crystals are arranged such that a-axes or c-axes of the seed crystals that are adjacent to each other almost coincide with each other between the units that are adjacent to each other.

15. The method according to claim 13 , wherein
each seed crystal has a c-plane,
in the seed crystal selection step, the c-planes are selected as crystal growth planes of the seed crystals, and
the seed crystals are arranged such that a-axes of the seed crystals that are adjacent to each other almost coincide with each other between the units that are adjacent to each other.

16. The method according to claim 15 , wherein
in the Group III nitride crystal liquid phase growth step, the seed crystals are arranged such that apexes of hexagons of the Group III nitride crystal grown from the seed crystals that are adjacent to each other almost coincide with each other between the units that are adjacent to each other.

17. The method according to claim 9 , wherein
the mask or the substrate comprises at least one selected from the group consisting of Al x Ga 1−x N (0<x≤1), an oxide of the Al x Ga 1−x N (0<x≤1), diamond-like carbon, silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, silicon carbide, yttrium oxide, yttrium aluminum garnet (YAG), tantalum, rhenium, and tungsten.

18. The method according to claim 9 , wherein
the through holes of the mask or the Group III nitride crystals arranged on the substrate each have a dot shape.

19. The method according to claim 18 , wherein
the through holes of the mask or the Group III nitride crystals arranged on the substrate are aligned at substanti

Assignees

• Univ Osaka
• Itochu Plastics Inc

Inventors

• Mori Yusuke
• Yoshimura Masashi
• Imade Mamoru
• Isemura Masashi
• Usui Akira
• Shibata Masatomo
• Yoshida Takehiro

Classifications

• H10P95/112

  leaving a reusable substrate, e.g. epitaxial lift off · CPC title

• H10P14/3446

  Transition metal elements; Rare earth elements · CPC title

• H10P14/3444

  P-type · CPC title

• H10P14/3442

  N-type · CPC title

• H10P14/3416

  Nitrides · CPC title