Voltage breakdown resistant monocrystalline silicon carbide semiconductor devices

• US 5,449,925 A
• Filed: 05/04/1994
• Issued: 09/12/1995
• Est. Priority Date: 05/04/1994
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures Holding 78 LLC (Intellectual Ventures LLC)
• Original Assignee: North Carolina State University (University of North Carolina System)
• Inventors: Baliga, Bantval J., Alok, Dev
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): Tang, Alice W.
• Application Number:
  US08/238,228
• Time in Patent Office: 496 Days
• Field of Search: 257/76, 257/77, 257/489, 257/491, 257/500, 257/504, 257/510, 257/513, 257/516, 257/523, 257/617, 257/626
• US Class Current: 257/77
• CPC Class Codes: H01L 29/1608 Silicon carbide
• CPC Class Codes: H01L 29/6606 the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor

Abstract

Voltage breakdown resistant monocrystalline silicon carbide semiconductor devices are obtained by forming an amorphous silicon carbide termination region in a monocrystalline silicon carbide substrate, at a face thereof, adjacent and surrounding a silicon carbide device. The amorphous termination region is preferably formed by implanting electrically inactive ions, such as argon, into the substrate face at sufficient energy and dose to amorphize the substrate face. The device contact or contacts act as an implantation mask to provide a self-aligned termination region for the device. The terminated devices may exhibit voltage breakdown resistance which approaches the ideal value for silicon carbide.

Claims

1. A breakdown resistant contact for a silicon carbide semiconductor device, comprising:

a contact region on a face of a monocrystalline silicon carbide substrate; and

an amorphous silicon carbide region in said monocrystalline silicon carbide substrate, at said face, adjacent and surrounding said contact region.

2. A breakdown resistant contact according to claim 1 wherein said amorphous silicon carbide region includes electrically inactive ions therein.

3. A breakdown resistant contact according to claim 2 wherein said amorphous silicon carbide region includes argon ions therein.

4. A breakdown resistant contact according to claim 1 wherein said amorphous silicon carbide region is an unannealed amorphous silicon carbide region.

5. A breakdown resistant contact according to claim 1 wherein said contact region forms a Schottky barrier with said monocrystalline silicon carbide substrate at said face to thereby produce a Schottky barrier rectifier silicon carbide device.

6. A semiconductor device comprising:

a monocrystalline silicon carbide substrate;

a silicon carbide device in said monocrystalline silicon carbide substrate, extending to a face thereof; and

an amorphous silicon carbide region in said monocrystalline silicon carbide substrate, at said face, adjacent and surrounding said silicon carbide device at said face.

7. A semiconductor device according to claim 6 wherein said amorphous silicon carbide region includes electrically inactive ions therein.

8. A semiconductor device according to claim 7 wherein said amorphous region includes argon ions therein.

9. A semiconductor device according to claim 6 wherein said amorphous silicon carbide region is an unannealed amorphous silicon carbide region.

10. A silicon carbide Schottky barrier rectifier comprising:

a monocrystalline silicon carbide substrate;

a contact on said monocrystalline silicon carbide substrate at a face thereof, wherein said contact forms a Schottky barrier with said monocrystalline silicon carbide substrate at said face; and

an amorphous silicon carbide region in said monocrystalline silicon carbide substrate, at said face, adjacent and surrounding said contact.

11. A silicon carbide Schottky barrier rectifier according to claim 10 wherein said amorphous silicon carbide region includes electrically inactive ions therein.

12. A silicon carbide Schottky barrier rectifier according to claim 11 wherein said amorphous silicon carbide region includes argon ions therein.

13. A silicon carbide Schottky barrier rectifier according to claim 10 wherein said amorphous silicon carbide region is an unannealed amorphous silicon carbide region.

14. A silicon carbide rectifier according to claim 10 wherein said amorphous silicon carbide region includes electrically inactive ions therein.

15. A silicon carbide rectifier according to claim 14 wherein said amorphous silicon carbide region includes argon ions therein.

16. A silicon carbide rectifier comprising:

a monocrystalline silicon carbide substrate of first conductivity type;

a monocrystalline silicon carbide region of second conductivity type in said monocrystalline silicon carbide substrate extending to a face thereof;

a contact on said monocrystalline silicon carbide region at said face; and

an amorphous silicon carbide region in said monocrystalline silicon carbide substrate, at said face, adjacent and surrounding said contact.

17. A silicon carbide rectifier according to claim 16 wherein said amorphous silicon carbide region is an unannealed amorphous silicon carbide region.