Electrical contact connection on silicon carbide substrate

Patent metadata

Field	Value
Publication number	US-11043383-B2
Application number	US-201916422373-A
Country	US
Kind code	B2
Filing date	May 24, 2019
Priority date	May 28, 2018
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A process for producing an electrical contact with a first metal layer and at least one second metal layer on a silicon carbide substrate includes removing at least some of the carbon residue by a chemical cleaning process, to clean the first metal layer. The first metal layer and/or the at least one second metal layer may be generated by sputtering deposition.

First claim

What is claimed is:

1. A method for producing an electrical contact with a first metal layer and at least one second metal layer on a silicon carbide substrate, the method comprising:
depositing the first metal layer on the silicon carbide substrate;
heat-treating the first metal layer to form a carbon residue;
removing at least some of the carbon residue by a first chemical cleaning process, to clean the first metal layer, wherein an oxide residue forms on the first metal layer during the first chemical cleaning process;
removing at least some of the oxide residue by a second chemical cleaning process different than the first chemical cleaning process, to clean the first metal layer; and
after both the first chemical cleaning process and the second chemical cleaning process, depositing the at least one second metal layer onto a surface of the cleaned first metal layer.

2. The method of claim 1 , wherein the first chemical cleaning process converts the carbon residue to a gas phase.

3. The method of claim 1 , wherein the first chemical cleaning process comprises supplying oxygen plasma.

4. The method of claim 1 , wherein the second chemical cleaning process comprises chemical etching.

5. The method of claim 4 , wherein the chemical etching is performed with hydrofluoric acid.

6. The method of claim 4 , wherein the chemical etching is performed with sulfuric acid.

7. The method of claim 1 , wherein depositing the first metal layer comprises a first sputtering deposition, and wherein depositing the at least one second metal layer comprises at least a second sputtering deposition.

8. The method of claim 1 , wherein depositing the at least one second metal layer onto the surface of the cleaned first metal layer comprises depositing multiple second metal layers in situ.

9. The method of claim 1 , wherein the at least one second metal layer comprises one or more layers selected from the group consisting of: a titanium layer; an aluminum layer; a nickel-silicon layer; a nickel-vanadium layer; and a gold-tin layer.

10. The method of claim 1 , wherein the at least one second metal layer comprises one or more layers selected from the group consisting of: a titanium layer; an aluminum layer; a nickel-containing layer; and a silver layer.

11. The method of claim 1 , wherein the at least one second metal layer comprises a buffer layer configured to buffer mechanical tensions within the at least one second metal layer.

12. The method of claim 1 , wherein the first chemical cleaning process comprises supplying a nitrogen oxide plasma.

Assignees

• Infineon Technologies Ag

Inventors

• Krivec Stefan
• Kern Ronny
• Kramp Stefan
• Langer Gregor
• Winkler Hannes
• Woehlert Stefan

Classifications

• H10P70/27 Primary

  during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers · CPC title

• H10W72/952

  comprising metals or metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/923

  Bond pads having multiple stacked layers · CPC title

• H10W72/59

  Bond pads specially adapted therefor · CPC title

• H10W72/019

  of bond pads · CPC title