FABRICATING A GALLIUM NITRIDE LAYER WITH DIAMOND LAYERS

• US 20100155901A1
• Filed: 12/22/2008
• Published: 06/24/2010
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Bernstein, Steven D., Korenstein, Ralph, Pereira, Stephen J.
• Granted Patent: US 7,888,171 B2
• Time in Patent Office: Days
• US Class Current: 257/615
• CPC Class Codes: H01L 21/02389 Nitrides
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02527 Carbon, e.g. diamond-like carbon
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 29/1602 Diamond
• CPC Class Codes: H01L 29/267 in different semiconductor regions , e.g. heterojunctions H01L29/263 takes precedence
• CPC Class Codes: H01L 29/66431 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT with an active layer made of a group 13/15 material H01L29/66462
• CPC Class Codes: H01L 29/66462 with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
• CPC Class Codes: H01L 29/7786 with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT

Abstract

In one aspect, a method includes fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity greater than the first thermal conductivity. The fabricating includes using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer onto the first diamond layer.

Claims

1. A method, comprising:

fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity greater than the first thermal conductivity, the fabricating comprising;

using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer onto the first diamond layer.

2. The method of claim 1 wherein using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer on the first diamond layer comprises using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer is about 2 mils.

3. The method of claim 2 wherein using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer on the first diamond layer comprises using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer is about 2 mils on the first diamond layer less than about 1 mil.

4. The method of claim 1 wherein using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer on the first diamond layer comprises using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer is about 4 mils.

5. The method of claim 1 wherein fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity greater than the first thermal conductivity comprises fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity twice the first thermal conductivity.

6. The method of claim 1 wherein the fabricating further comprises using a hot filament CVD process to form the first diamond layer.

7. The method of claim 1 wherein the fabricating further comprises growing the GaN layer on a first substrate.

8. The method of claim 7 wherein growing the GaN layer on a first substrate comprises growing the GaN layer on one of silicon carbide, silicon or sapphire.

9. The method of claim 7 wherein the fabricating further comprises:

disposing a layer of material onto the GaN layer; and

removing the first substrate.

10. The method of claim 9 wherein disposing a layer of material onto the GaN layer comprises disposing one of a silicon layer or a glass layer.

11. The method of claim 9 wherein the fabricating further comprises:

depositing the first diamond layer on a second substrate; and

removing the second substrate.

12. The method of claim 11 wherein depositing the first diamond layer on a second substrate comprises depositing the first diamond layer on a silicon substrate

13. The method of claim 11 wherein the fabricating further comprises:

attaching the first and second diamond layers to the GaN layer; and

removing the layer of material.

14. The method of claim 1 wherein the fabricating further comprises:

depositing the first diamond layer on to a silicon-on-insulator (SOI) substrate;

removing an oxide from the SOI substrate; and

growing the GaN layer on remaining SOI substrate.

15. The method of claim 1 wherein fabricating a gallium nitride (GaN) layer with a first diamond layer comprises disposing the first diamond layer on a first surface of the GaN, and

further comprising disposing a third diamond layer on a second surface of the GaN layer opposite the first surface of the GaN layer.

16. The method of claim 1 wherein fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity greater than the first thermal conductivity comprises fabricating a GaN layer comprising at least one of undoped GaN, doped GaN or GaN combined with another element.

17. The method of claim 1, further comprising fabricating at least one of a high frequency device, a high electron mobility transistor (HEMT) or a microwave device from the gallium nitride (GaN) layer with the first diamond and the second diamond layer.

18. A method, comprising:

fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity twice the first thermal conductivity, the fabricating comprising;

using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer of between about 2 mils to about 4 mils on the first diamond layer of less than about 1 mil.

19. The method of claim 18 wherein the fabricating further comprises using a hot filament CVD process to form the first diamond layer.

20. The method of claim 18 wherein using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer on the first diamond layer comprises using a microwave plasma chemical vapor deposition (CVD) process to deposit the second diamond layer is about 4 mils.

21. The method of claim 18 wherein the fabricating further comprises:

growing the GaN layer on a first substrate;

disposing a silicon layer onto the GaN layer;

removing the first substrate;

depositing the first diamond layer onto a second substrate;

removing the second substrate;

attaching the first and second diamond layers to the GaN layer; and

removing the silicon layer.

22. The method of claim 18 wherein the fabricating further comprises:

depositing the first diamond layer on to a silicon-on-insulator (SOI) substrate;

removing an oxide from the SOI substrate; and

growing the GaN on a remaining SOI substrate.

23. The method of claim 18 wherein fabricating a gallium nitride (GaN) layer with a first diamond layer comprises disposing the first diamond layer on a first surface of the GaN and further comprising disposing a third diamond layer on a second surface of the GaN layer opposite the first surface of the GaN layer.

24. The method of claim 18 wherein fabricating a gallium nitride (GaN) layer with a first diamond layer having a first thermal conductivity and a second diamond layer having a second thermal conductivity comprises fabricating a GaN layer comprising at least one of undoped GaN, doped GaN or GaN combined with another element.

25. The method of claim 18, further comprising fabricating at least one of a high frequency device, a high electron mobility transistor (HEMT) or a microwave device from the gallium nitride (GaN) layer with the first diamond and the second diamond layer.

26. A device, comprising:

a gallium nitride (GaN) layer;

a first layer of diamond having a first thermal conductivity disposed on the GaN layer; and

a second layer of diamond having a second thermal conductivity greater than the first thermal conductivity deposited on the first layer of diamond.

27. The device of claim 26, further comprising an interlayer disposed between the first layer of diamond and the GaN layer.

28. The device of claim 26 wherein the second diamond layer is between about 2 mils and about 4 mils and the first diamond layer is less than about 1 mil.

29. The device of claim 26 wherein the second diamond layer about 4 mils or greater and the first diamond layer is less than about 1 mil.

30. The device of claim 26 wherein the device is one of a high frequency device, a high electron mobility transistor (HEMT) or a microwave device.

31. The device of claim 26 wherein the first layer of diamond is disposed on a first surface of the GaN layer, the GaN layer further comprising a third diamond layer disposed on a second surface of the GaN layer opposite the first surface of the GaN layer.

32. The device of claim 26 wherein the GaN layer comprises at least one undoped GaN, doped GaN or GaN combined with another element.