Epitaxial structure

Patent metadata

Field	Value
Publication number	US-11532700-B2
Application number	US-202217689995-A
Country	US
Kind code	B2
Filing date	Mar 9, 2022
Priority date	Aug 1, 2018
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

An epitaxial structure includes a substrate, a nucleation layer, a buffer layer, and a nitride layer orderly. The nucleation layer consists of regions in a thickness direction, wherein a chemical composition of the regions is Al(1−x)InxN, where 0≤x≤1. The x value consists of four sections of variation along the thickness direction, in which a first fixed region has a maximum value, a first gradient region gradually changes from the maximum value to a minimum value, a second fixed region has the minimum value, and a second gradient region gradually changes from the minimum value to the maximum value. An absolute value of a gradient slope of the first and second gradient regions is 0.1%/nm to 50%/nm. A surface roughness of the nucleation layer in contact with the buffer layer is greater than that of the buffer layer in contact with the nitride layer.

First claim

What is claimed is:

1. An epitaxial structure comprising:
a substrate;
a nucleation layer disposed on the substrate, wherein the nucleation layer consists of a plurality of regions in a thickness direction, and a chemical composition of the plurality of regions is Al (1−x) In x N, where 0≤x≤1, wherein the x value in the chemical composition of each four of the regions consists of four sections of variation along the thickness direction, the four sections of variation comprising: a first fixed region of a maximum value, a first gradient region gradually changing from the maximum value to a minimum value, a second fixed region of the minimum value, and a second gradient region gradually changing from the minimum value to the maximum value, wherein an absolute value of a gradient slope of the first gradient region and the second gradient region is 0.1%/nm to 50%/nm;
a buffer layer disposed on the nucleation layer, wherein a thickness of the nucleation layer is less than a thickness of the buffer layer; and
a nitride layer disposed on the buffer layer, wherein a roughness of a surface of the nucleation layer in contact with the buffer layer is greater than a roughness of a surface of the buffer layer in contact with the nitride layer.

2. The epitaxial structure according to claim 1 , wherein the absolute value of the gradient slope of the first gradient region and the second gradient region is 0.5%/nm to 10%/nm.

3. The epitaxial structure according to claim 1 , wherein an initial content of the x value of the nucleation layer is 10% to 100%, an end content of the x value is 0% to 90%, and an initial content of the (1−x) value is 0% to 90%, and an end content of the (1−x) value is 10% to 100%, wherein the initial content of the x value is located on a bottom portion of the nucleation layer close to the substrate, and the end content of the x value is located on a top portion of the nucleation layer close to the buffer layer.

4. The epitaxial structure according to claim 3 , wherein the initial content of the x value of the nucleation layer is 50% to 100%, the end content of the x value is 0% to 50%, the initial content of the (1−x) value is 0% to 50%, and the end content of the (1−x) value is 50% to 100%.

5. The epitaxial structure according to claim 1 , wherein the thickness of the nucleation layer is 1 nm to 500 nm.

6. The epitaxial structure according to claim 5 , wherein the thickness of the nucleation layer is 1 nm to 50 nm.

7. The epitaxial structure according to claim 1 , wherein a number of the plurality of regions of the nucleation layer is 4 to 100.

8. The epitaxial structure according to claim 7 , wherein the number of the plurality of regions of the nucleation layer is 4 to 20.

9. The epitaxial structure according to claim 1 , wherein the roughness of the surface of the nucleation layer in contact with the buffer layer is 1 nm to 10 nm.

10. The epitaxial structure according to claim 9 , wherein the roughness of the surface of the nucleation layer in contact with the buffer layer is 1 nm to 3 nm.

Assignees

• Globalwafers Co Ltd

Inventors

• Liu Jia-Zhe
• Huang Yen-Lun
• Shih Ying-Ru

Classifications

• H10P14/3416

  Nitrides · CPC title

• H10P14/3216 Primary

  Nitrides · CPC title

• C30B29/403

  AIII-nitrides · CPC title

• C30B25/20

  the substrate being of the same materials as the epitaxial layer · CPC title

• C30B25/183

  being provided with a buffer layer, e.g. a lattice matching layer · CPC title