Group 13 element nitride crystal substrate and function element

Patent metadata

Field	Value
Publication number	US-2019360119-A9
Application number	US-201815991317-A
Country	US
Kind code	A9
Filing date	May 29, 2018
Priority date	Dec 11, 2015
Publication date	Nov 28, 2019
Grant date	—

Abstract

A crystal substrate 1 includes an underlying layer 2 and a thick film 3. The underlying layer 2 is composed of a crystal of a nitride of a group 13 element and includes a first main face 2a and a second main face 2b. The thick film 3 is composed of a crystal of a nitride of a group 13 element and provided over the first main face of the underlying layer. The underlying layer 2 includes a low carrier concentration region 5 and a high carrier concentration region 4 both extending between the first main face 2a and the second main face 2b. The low carrier concentration region 5 has a carrier concentration of 1017/cm3 or lower and a defect density of 107/cm2 or lower. The high carrier concentration region 4 has a carrier concentration of 1019/cm3 or higher and a defect density of 108/cm2 or higher. The thick film 3 has a carrier concentration of 1018/cm3 or higher and 1019/cm3 or lower and a defect density of 107/cm2 or lower.

First claim

What is claimed is:

1 . A group 13 nitride crystal substrate comprising an underlying layer and a thick layer:
said underlying layer comprising a crystal of a nitride of a group 13 element and having a first main face and a second main face; said thick film comprising a crystal of a nitride of a group 13 element and provided over said first main face of said underlying layer; wherein said underlying layer comprises a low carrier concentration region and a high carrier concentration region both extending between said first main face and said second main face; wherein said low carrier concentration region has a carrier concentration of 1×10 16 /cm 3 or higher and 10 17 /cm 3 or lower; wherein said low carrier concentration region has a defect density of 2×10 6 /cm 2 or higher and 10 7 /cm 2 or lower; wherein said high carrier concentration region has a carrier concentration of 10 19 /cm 3 or higher and 5×10 19 /cm 3 or lower; wherein said high carrier concentration region has a defect density of 10 8 /cm 2 or higher and 5×10 8 /cm 2 or lower; wherein said thick film has a carrier concentration of 10 18 /cm 3 or higher and 10 19 /cm 3 or lower; and wherein said thick film has a defect density of 10 7 /cm 2 or lower.

2 . The crystal substrate of claim 1 , wherein a defect density at a surface of said thick film is 10 7 /cm 2 or lower.

3 . The crystal substrate of claim 1 , wherein said thick film has a thickness of 1 μm or larger and wherein said underlying layer has a thickness of 50 μm or larger and 200 μm or smaller.

4 . The crystal substrate of claim 1 , wherein said thick film is formed by a flux method or a vapor phase method.

5 . The crystal substrate of claim 1 , wherein a surface of said thick film comprises a polished surface.

6 . The crystal substrate of claim 1 , wherein said crystal of said nitride of said group 13 element forming said underlying layer and said crystal of said nitride of said group 13 element forming said thick film comprises gallium nitride.

7 . A functional device comprising said crystal substrate of claim 1 and a functional layer formed over said thick film of said crystal substrate and comprising a nitride of a group 13 element.

8 . The functional device of claim 7 , wherein said functional layer has a function of emitting a light.

9 . The functional device of claim 7 , further comprising a seed crystal comprising a nitride of a group 13 element, wherein said crystal substrate is provided over said seed crystal.

Assignees

• Ngk Insulators Ltd

Inventors

• Iwai Makoto
• Yoshino Takashi

Classifications

• H10P14/3441

  Conductivity type · CPC title

• H10P14/3416

  Nitrides · CPC title

• H10P14/3251

  consisting of three or more layers · CPC title

• H10P14/3242

  Structure · CPC title

• H10P14/3216

  Nitrides · CPC title