AIN buffer N-polar GaN HEMT profile

1. An N-face GaN semiconductor device comprising:

a substrate;

a buffer layer including aluminum deposited on the substrate;

a barrier layer including aluminum deposited on the buffer layer; and

a GaN channel layer deposited on the barrier layer, where the channel layer, the barrier layer and the buffer layer create a two-dimensional electron gas (2-DEG) layer at a transition between the channel layer and the barrier layer.

2. The device according to claim 1 wherein the buffer layer is an AlN buffer layer.

3. The device according to claim 1 wherein the buffer layer is an AlGaN buffer layer.

4. The device according to claim 1 wherein the barrier layer is an AlGaN barrier layer.

5. The device according to claim 4 wherein the AlGaN barrier layer is a graded layer where the aluminum and the gallium in the barrier layer is selectively graded from a higher concentration of aluminum and a lower concentration of gallium at a transition between the buffer layer and the barrier layer to a lower concentration of aluminum and a higher concentration of gallium at a transition between the barrier layer and the channel layer.

6. The device according to claim 1 wherein the barrier layer is an AlN barrier layer.

7. The device according to claim 1 wherein the semiconductor device is a high electron mobility transistor (HEMT) device.

8. The device according to claim 1 wherein the substrate is a silicon carbide (SiC) substrate.

9. An N-face GaN high electron mobility transistor (HEMT) device comprising:

a silicon carbide (SiC) substrate;

a buffer layer including aluminum deposited on the substrate;

a barrier layer including aluminum deposited on the buffer layer; and

a GaN channel layer deposited on the barrier layer, where the channel layer, the barrier layer and the buffer layer create a two-dimensional electron gas (2-DEG) layer at a transition between the channel layer and the barrier layer.

10. The device according to claim 9 wherein the buffer layer is an AlN buffer layer.

11. The device according to claim 9 wherein the buffer layer is an AlGaN buffer layer.

12. The device according to claim 9 wherein the barrier layer is an AlGaN barrier layer.

13. The device according to claim 12 wherein the AlGaN barrier layer is a graded layer where the aluminum and the gallium in the barrier layer is selectively graded from a higher concentration of aluminum and a lower concentration of gallium at a transition between the buffer layer and the barrier layer to a lower concentration of aluminum and a higher concentration of gallium at a transition between the barrier layer and the channel layer.

14. The device according to claim 9 wherein the barrier layer is an AlN barrier layer.

15. A method for forming an N-face GaN semiconductor device, said method comprising:

providing a substrate;

epitaxially growing a buffer layer on a face of the substrate that creates an N-face oriented device where the buffer layer includes aluminum;

epitaxially growing a barrier layer including aluminum on the buffer layer; and

epitaxially growing a GaN channel layer on the barrier layer so that the channel layer, the barrier layer and the buffer layer create a two-dimensional electron gas (2-DEG) layer at a transition between the channel layer and the barrier layer.

16. The method according to claim 15 wherein epitaxially growing the buffer layer includes epitaxially growing an AlN buffered layer.

17. The method according to claim 15 wherein epitaxially growing the buffer layer includes epitaxially growing an AlGaN buffer layer.

18. The method according to claim 15 wherein epitaxially growing the barrier layer includes epitaxially growing an AlGaN barrier layer.

19. The method according to claim 15 wherein epitaxially growing the barrier layer includes epitaxially growing an AlN barrier layer.

20. The method according to claim 15 wherein the semiconductor device is a high electron mobility transistor (HEMT) device.