METHOD FOR TREATING SURFACE OF SEMICONDUCTOR LAYER, SEMICONDUCTOR SUBSTRATE, METHOD FOR MAKING EPITAXIAL SUBSTRATE

• US 20170278702A1
• Filed: 06/07/2017
• Published: 09/28/2017
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Sumitomo Electric Device Innovations Incorporated (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Device Innovations Incorporated (Sumitomo Corporation)
• Inventors: Watanabe, Tadashi
• Granted Patent: US 10,109,482 B2
• Time in Patent Office: Days
• CPC Class Codes: C23C 16/303 Nitrides
• CPC Class Codes: C23C 16/4401 Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/30612 Etching of AIIIBV compounds
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/7786 with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT

Abstract

A surface treatment method for a semiconductor layer includes growing a first layer on a substrate in a growth reactor, the first layer consisting of one of gallium nitride, aluminum gallium nitride and indium aluminium nitride; growing a second layer of gallium nitride on a surface of the first layer, the gallium nitride of the second GaN layer having a composition ratio of gallium to nitrogen larger than 2; taking the substrate out of the growth reactor after growing the second layer; and removing the second layer after taking the substrate out of the growth reactor.

Claims

1. A method for treating a surface of a semiconductor layer, the method comprising the steps of:

growing a first layer on a substrate in a growth reactor, the first layer consisting of one of gallium nitride, aluminum gallium nitride and indium aluminum nitride;

growing a second layer made of gallium nitride on a surface of the first layer, the second layer having a composition ratio of gallium to nitrogen larger than 2;

taking the substrate out of the growth reactor after growing the second layer; and

removing the second layer after taking the substrate out of the growth reactor.

2. The method according to claim 1,

wherein the step of growing the second layer on the surface of the first layer includes a step of forming the second layer by setting a substrate temperature equal to or lower than 800 degrees Celsius in the growth reactor.

3. The method according to claim 1,

wherein the step of removing the second layer includes a step of removing the second layer using mixed liquid including sulfuric acid and hydrogen peroxide.

5. The method according to claim 1,

further including steps of, after the step of growing the second layer,

forming an accreting object on the second layer before the step of taking the substrate out of the growth reactor, and

removing the accreting object after the step of taking the substrate out of the growth reactor but before the step of removing the second layer.

6. The method according to claim 1,

wherein the step of growing the first layer and the step of growing the second layer are continuously performed in the growth reactor.

4. (canceled)

7-10. -10. (canceled)

11. A method for making an epitaxial substrate, comprising the steps of:

growing a first layer on a substrate in a growth reactor, the first layer consisting of one of gallium nitride, aluminum gallium nitride and indium aluminum nitride;

growing a second layer made of gallium nitride compound on a surface of the first layer in the growth reactor, the first layer being in contact with the second layer, and the gallium nitride compound having a composition ratio of gallium to nitrogen larger than 2;

taking the substrate out of the growth reactor after growing the second layer; and

exposing the first layer by etching the second layer after taking the substrate out of the growth reactor.

12. The method according to claim 11,

wherein the step of growing the second layer includes a step of setting a substrate temperature equal to or lower than 800 degrees Celsius in the growth reactor.

13. The method according to claim 11,

wherein the step of exposing the first layer includes a step of etching the second layer using mixed liquid containing sulfuric acid and hydrogen peroxide.

15. The method according to claim 11,

further including a step of forming an accreting object on the second layer after the step of growing the second layer but before the step of taking the substrate out of the growth reactor, and a step of removing the accreting object before the step of exposing the first layer.

14. (canceled)