Silicon carbide device and method for forming a silicon carbide device

Patent metadata

Field	Value
Publication number	US-11367683-B2
Application number	US-201916453222-A
Country	US
Kind code	B2
Filing date	Jun 26, 2019
Priority date	Jul 3, 2018
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

A silicon carbide device includes a silicon carbide substrate, a contact layer including nickel, silicon and aluminum, a barrier layer structure including titanium and tungsten, and a metallization layer including copper. The contact layer is located on the silicon carbide substrate. The contact layer is located between the silicon carbide substrate and at least a part of the barrier layer structure. The barrier layer structure is located between the silicon carbide substrate and the metallization layer.

First claim

What is claimed is:

1. A silicon carbide device, comprising:
a silicon carbide substrate;
a contact layer located on the silicon carbide substrate and comprising nickel, silicon and aluminum;
a barrier layer structure comprising titanium and tungsten; and
a metallization layer comprising copper,
wherein the contact layer is located between the silicon carbide substrate and at least a part of the barrier layer structure,
wherein the barrier layer structure is located between the silicon carbide substrate and the metallization layer,
wherein the metallization layer is configured as a contact pad of the silicon carbide device.

2. The silicon carbide device of claim 1 , wherein the barrier layer structure comprises a TiW layer.

3. The silicon carbide device of claim 2 , wherein the TiW layer contacts the metallization layer.

4. The silicon carbide device of claim 1 , wherein the barrier layer structure comprises a TiWN layer.

5. The silicon carbide device of claim 4 , wherein the TiWN layer contacts the metallization layer.

6. The silicon carbide device of claim 1 , wherein the barrier layer structure contacts the contact layer.

7. The silicon carbide device of claim 1 , wherein the barrier layer structure comprises a Ti/TiN layer, and/or a TiW layer, and/or a TiWN layer, and/or a MoN layer.

8. The silicon carbide device of claim 1 , wherein the barrier layer structure comprises a Ti/TiN layer.

9. The silicon carbide device of claim 8 , wherein the Ti/TiN layer contacts the contact layer.

10. The silicon carbide device of claim 8 , wherein the barrier layer structure further comprises a TiW layer and/or a TiWN layer.

11. The silicon carbide device of claim 8 , wherein a titanium layer of the Ti/TiN layer contacts the contact layer.

12. The silicon carbide device of claim 1 , wherein a vertical thickness of the barrier layer structure is at least 100 nm and at most 600 nm.

13. The silicon carbide device of claim 1 , wherein the contact layer is a NiSiAl layer.

14. The silicon carbide device of claim 1 , wherein the contact layer comprises at least 1% and at most 20% silicon by volume.

15. The silicon carbide device of claim 1 , wherein the contact layer comprises at most 10% carbon inclusions by volume.

16. The silicon carbide device of claim 1 , wherein the contact layer is in ohmic contact with a first doping region of the silicon carbide substrate and/or with a second doping region of the silicon carbide substrate, wherein the first doping region has a first conductivity type, and wherein the second doping region has a second conductivity type.

17. The silicon carbide device of claim 1 , wherein the metallization layer comprises at least 60% copper by volume.

18. The silicon carbide device of claim 1 , wherein the metallization layer is at least 5 times thicker than each of the contact layer and the barrier layer structure.

19. The silicon carbide device of claim 1 , further comprising a bondwire bonded to the metallization layer.

20. The silicon carbide device of claim 19 , wherein the bondwire has a diameter of at most 100 μm.

21. The silicon carbide device of claim 19 , wherein the bondwire is a copper bondwire.

22. The silicon carbide device of claim 1 , further comprising a gate contact pad or a sense contact pad at least partially formed by the metallization layer, wherein a lateral surface area of the gate contact pad or sense contact pad is at most 200 μm by 200 μm.

23. The silicon carbide device of claim 1 , wherein at least one of a transistor structure and/or a diode structure of the silicon carbide device has a breakdown voltage of more than 100V.

24. A method for forming a silicon carbide device, the method comprising:
forming a contact layer comprising nickel, silicon and aluminum on a silicon carbide substrate of the silicon carbide device;
after forming the contact layer, forming a barrier layer structure comprising titanium and tunbsten; and
after forming the barrier layer structure, forming a metallization layer comprising copper, so that an ohmic connection is formed between the metallization layer and a doping region of the silicon carbide substrate via the barrier layer structure and the contact layer.

25. The silicon carbide device of claim 1 , wherein a lateral dimension of the contact pad is at least 100 μm, and wherein a vertical thickness of the of the contact pad is

Assignees

• Infineon Technologies Ag

Inventors

• Fuergut Edward
• Joshi Ravi Keshav
• Siemieniec Ralf
• Basler Thomas
• Gruber Martin
• Hilsenbeck Jochen
• Peters Dethard
• Rupp Roland
• Scholz Wolfgang

Classifications

• H10W72/552

  comprising metals or metalloids, e.g. silver · CPC title

• H10W72/5522

  comprising gold [Au] · CPC title

• H10W72/536

  the connected ends being ball-shaped · CPC title

• H10W72/5475

  multiple bond wires connected to common bond pads at both ends of the wires · CPC title

• H10W72/5473

  multiple bond wires connected to a common bond pad · CPC title