Strained diamond growing and doping method based on chemical vapor deposition (CVD) method

Patent metadata

Field	Value
Publication number	US-11519097-B1
Application number	US-202217849761-A
Country	US
Kind code	B1
Filing date	Jun 27, 2022
Priority date	Jan 5, 2022
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

The present disclosure relates to a method for growing and doping a strained diamond based on a chemical vapor deposition (CVD) method. The method comprises: depositing a gradient buffer layer and a relaxation layer on a substrate layer in sequence by the CVD method; and finally, depositing a CVD strained diamond layer on the relaxation layer and performing doping by the CVD method. According to the method, a lattice constant of the relaxation layer prepared by utilizing the CVD method is greater than a lattice constant of the diamond, so that a diamond generates a stretching strain. In growing and doping processes, the CVD strained diamond is in a stretching strain state. Therefore, a formation energy of a doped element is low, and it is easy to dope the diamond, so that a doping concentration of the diamond is high.

First claim

What is claimed is:

1. A method for growing and doping a strained diamond based on a chemical vapor deposition (CVD) method, comprising the following steps:
Step 1: performing preparatory work of a substrate layer: placing the substrate layer on a sample stage of a CVD device;
Step 2: growing an X a C 1-a gradient buffer layer by CVD: introducing a mixed gas of a gas containing an element X, a methane gas and hydrogen to prepare the X a C 1-a gradient buffer layer, wherein a is a proportion of the element X in X a C 1-a ;
Step 3: growing an X b C 1-b relaxation layer by CVD: introducing a mixed gas of a gas containing an element X, a methane gas and hydrogen, and fixing a flow of the gas containing the element X to make a component X of the X b C 1-b relaxation layer be kept constant in a perpendicular direction so as to prepare the X b C 1-b relaxation layer, wherein b is a proportion of the element X in X b C 1-b , X is a lattice constant adjusting element, and C is an element carbon;
Step 4: growing and doping a CVD strained diamond layer by CVD: introducing a mixed gas containing a doping gas, a methane gas and hydrogen to make the diamond be doped while growing so as to grow the CVD strained diamond layer on the X b C 1-b relaxation layer, wherein a lattice constant of the X b C 1-b relaxation layer is greater than a diamond lattice constant of the CVD strained diamond layer, so that the CVD strained diamond layer is in a stretching strain state; and
Step 5: stripping the substrate layer to obtain a diamond-doped epitaxial structure.

2. The method for growing and doping a strained diamond based on a CVD method according to claim 1 , wherein the element X is an element germanium or silicon.

3. The method for growing and doping a strained diamond based on a CVD method according to claim 1 , wherein in Step 2, when the substrate layer is made from a silicon single crystal material, a value of a is decreased gradually with passage of a deposition time, namely, it is to set that the flow of the gas containing the element X is decreased gradually over time; and when the substrate layer is made from a diamond single crystal material, the value of a is increased gradually with passage of the deposition time, namely, it is to set that the flow of the gas containing the element X is increased gradually over time.

4. The method for growing and doping a strained diamond based on a CVD method according to claim 3 , wherein the components of the introduced mixed gas in Step 3 are constant in proportion, and a flow ratio of the gas containing the element X to the introduced methane gas is substantially equal to a flow ratio of the gas containing the element X to the introduced methane gas at the end in Step 2.

5. The method for growing and doping a strained diamond based on a CVD method according to claim 3 , wherein in each of Step 2 and Step 3, the flow ratio of the introduced methane gases to hydrogen in the introduced mixed gas ranges from 0.1% to 20%.

6. The method for growing and doping a strained diamond based on a CVD method according to claim 3 , wherein in each of Step 1, Step 2, Step 3 and the Step 4, the flow of the introduced hydrogen is 1-2000 sccm.

7. The method for growing and doping a strained diamond based on a CVD method according to claim 3 , wherein in Step 4, the flow ratio of the introduced doping gas to the introduced methane gas in the introduced mixed gas ranges from 0.1% to 50%.

8. The method for growing and doping a strained diamond based on a CVD method according to claim 1 , wherein the doping gas is any one of phosphine, hydrogen arsenide, oxygen and hydrogen sulfide.

9. The method for growing and doping a strained diamond based on a CVD method according to claim 1 , wherein a magnitude relationship between a lattice constant A1 of the single crystal material of the X b C 1-b relaxation layer and a diamond lattice constant A2 of the CVD strained diamond layer is: A1>A2 and A1<(1+9%)×A2.

10. The method for growing and doping a strained diamond based on a CVD method according to claim 1 , further comprising the following step:
Step 6: removing the substrate layer, the X a C 1-a gradient buffer layer and the X b C 1-b relaxation layer by an etching process to obtain a strainless doped diamond.

Assignees

• Univ Wuhan

Inventors

• Liu Sheng
• Shen Wei
• Wu Gai
• Guo Yuzheng
• Liang Kang
• Wang Qijun
• Wang Shizhao

Classifications

• C30B29/04 Primary

  Diamond · CPC title

• C30B25/183

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

• C30B25/18 Primary

  characterised by the substrate · CPC title

• C23C16/0272

  Deposition of sub-layers, e.g. to promote the adhesion of the main coating · CPC title

• C23C16/278 Primary

  doping or introduction of a secondary phase in the diamond · CPC title