Structure and method for III-nitride device isolation

• US 20060223275A1
• Filed: 05/19/2006
• Published: 10/05/2006
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Infineon Technologies Americas Corp. (Infineon Technologies AG)
• Original Assignee: International Rectifier Corporation (Infineon Technologies AG)
• Inventors: Bridger, Paul
• Granted Patent: US 8,748,204 B2
• Time in Patent Office: Days
• US Class Current: 438/318
• CPC Class Codes: H01L 21/7605 between components manufactured in an active substrate comprising AIII BV compounds
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/764 Air gaps H01L21/76264 takes precedence

Abstract

Isolation of III-nitride devices may be performed with a dopant selective etch that provides a smooth profile with little crystal damage in comparison to previously used isolation techniques. The dopant selective etch may be an electro-chemical or photo-electro-chemical etch. The desired isolation area may be identified by changing the conductivity type of the semiconductor material to be etched. The etch process can remove a conductive layer to isolate a device atop the conductive layer. The etch process can be self stopping, where the process automatically terminates when the selectively doped semiconductor material is removed.

Claims

1. A method of fabricating a semiconductor device comprising:

selectively changing the conductivity of portions of a III-nitride semiconductor body from one conductivity to another conductivity; and

charge-selectively removing said portions to obtain voids in said III-nitride semiconductor body.

2. The method of claim 1, wherein said III-nitride body is GaN based.

3. The method of claim 1, wherein said III-nitride body is disposed over a body layer.

4. The method of claim 1, wherein said body layer is comprised of at least one layer III-nitride material.

5. The method of claim 1, wherein said body layer is comprised of silicon.

6. The method of claim 1, wherein said body layer is comprised of silicon carbide.

7. The method of claim 1, wherein said body layer is comprised of sapphire.

8. The method of claim 1, wherein said body layer is comprised of a composite that includes graded III-nitride.

9. The method of claim 1, wherein said body layer is conductive.

10. The method of claim 1, wherein said body is comprised of a resistive material.

11. The method of claim 1, wherein said body is comprised of an insulating material.

12. The method of claim 1, wherein said III-nitride semiconductor body includes at least one III-nitride semiconductor device disposed thereon.

13. The method of claim 12, wherein said at least one III-nitride semiconductor device is one of a FET, a Schottky diode, and a rectifier.

14. The method of claim 1, wherein said selectively changing step is carried out through dopant implantation.

15. The method of claim 1, wherein said charge-selective removing step is carried out by an electrochemical etch.

16. The method of claim 1, wherein said charge-selective removing step is carried out by a photo electro-chemical etch.

17. The method of claim 1, further comprising filling said voids with a dielectric material.

18. The method of claim 1, further comprising passivating said voids.

19. A method for isolating III-nitride semiconductor devices, comprising:

selectively exposing a given surface area of a semiconductor material near a device to be isolated;

applying a dopant selective etch to the semiconductor material to remove the semiconductor material exposed in said given surface area.

20. The method according to claim 19, wherein the etch is an electro-chemical etch.

21. The method according to claim 19, wherein the etch is a photo-electro chemical etch.

22. The structure of claim 19, wherein said given surface area is selectively exposed by having a conductivity characteristic which is changed from that of the semiconductor material near said device to be isolated.

23. The method according to claim 22, wherein the etch is an electro-chemical etch.

24. The method according to claim 22, wherein the etch is a photo-electro chemical etch.