Single conductor alloy as diffusion barrier system and simulataneous OHMIC contact to N- and P-type silicon carbide

Patent metadata

Field	Value
Publication number	US-10056259-B1
Application number	US-201715722668-A
Country	US
Kind code	B1
Filing date	Oct 2, 2017
Priority date	Sep 30, 2016
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

Use of a single alloy conductor to form simultaneous ohmic contacts (SOC) to n- and p-type 4H-SiC. The single alloy conductor also is an effective diffusion barrier against gold (AU) and oxygen (O2) at high temperatures (e.g., up to 800° C.). The innovation may also provide an effective interconnecting metallization in a multi-level metallization device scheme.

First claim

What is claimed is:

1. A method for forming simultaneous ohmic contacts comprising:
creating a single alloy conductor comprising co-sputtered PtTi by phase segregation annealing (PSA); and
applying the single alloy conductor to a substrate comprising 4H-SiC having a p-type portion and an n-type portion, wherein the single alloy conductor stablishes the simultaneous ohmic contacts.

2. The method of claim 1 , wherein the single alloy conductor forms a film.

3. The method of claim 1 , wherein the single alloy conductor comprises Pt80-Ti20.

4. The method of claim 1 , wherein the single alloy conductor comprises Pt70-Ti30.

5. The method of claim 1 , further comprising:
depositing and patterning a diffusion barrier comprising a layer of single alloy conductor, wherein the layer is about 200 nm thick; and
annealing in ambient argon.

6. The method of claim 5 , wherein annealing takes place at about 700° C. for about 30 minutes.

7. The method of claim 5 , wherein the patterning comprises using an aluminum layer as the contact mask for pattern etching.

8. The method of claim 1 wherein PSA is achieved by annealing the single alloy conductor by vacuum RTA.

9. The method of claim 8 , further comprising annealing another layer of the single alloy conductor in argon.

10. The method of claim 9 , further comprising adding a sputtered capping layer.

11. The method of claim 10 , wherein the capping layer comprises Au.

Assignees

• Nasa
• The Us Admin Of National Aeronautics And Space Administration

Inventors

• Okojie Robert S

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P50/667

  by liquid etching only · CPC title

• H10P14/44

  Physical vapour deposition [PVD] · CPC title

• H10W20/4446

  Refractory-metal alloys · CPC title

• H10W20/4435

  Noble-metal alloys · CPC title