Direct growth of diamond in backside vias for GaN HEMT devices
A GaN high electron mobility transistor (HEMT) device having a silicon carbide substrate including a top surface and a bottom surface, where the substrate further includes a via formed through the bottom surface and into the substrate. The device includes a plurality of epitaxial layers provided on the top surface of the substrate, a plurality of device layers provided on the epitaxial layers, and a diamond layer provided within the via.
1. A semiconductor device comprising:
a substrate including a top surface and a bottom surface, said substrate further including a via formed through the bottom surface and into the substrate, wherein diamond is provided at least partially within the via in the substrate;
a plurality of GaN epitaxial layers grown directly on the top surface of the substrate; and
a plurality of device layers grown on the epitaxial layers.
2. The device according to claim 1 wherein the diamond is provided only within the via.
3. The device according to claim 1 wherein the diamond is provided as a layer on the bottom surface of the substrate.
4. The device according to claim 1 wherein the diamond completely fills the via.
5. The device according to claim 1 wherein the diamond only partially fills the via.
6. The device according to claim 1 wherein the via extends completely through the substrate.
7. The device according to claim 1 wherein the via extends only partially through the substrate.
8. The device according to claim 1 wherein the device is a GaN high electron mobility transistor device and the substrate is a silicon carbide substrate.
9. The device according to claim 1 wherein the diamond is multiple diamond layers of different diamond purity where the highest purity diamond layers are closest to the top surface of the substrate.
10. The device according to claim 1 wherein the diamond is a graded diamond layer that is graded by diamond purity where the highest purity diamond is closest to the top surface of the substrate.
11. The device according to claim 1 wherein the via has a width about the same size as a width of the device layers.
12. The device according to claim 1 wherein the diamond is a polycrystalline diamond.
13. A GaN high electron mobility transistor (HEMT) device comprising:
a silicon carbide substrate including a top surface and a bottom surface, said substrate further including a via formed through the bottom surface and into the substrate;
a plurality of GaN epitaxial layers grown directly on the top surface of the substrate;
a plurality of device layers grown on the epitaxial layers; and
a diamond layer provided within the via.
14. The device according to claim 13 wherein the via has a width about the same size as a width of the device layers.
15. The device according to claim 13 wherein the diamond layer is a polycrystalline diamond layer.
16. The device according to claim 13 wherein the diamond layer is provided only within the via.
17. The device according to claim 13 wherein the diamond layer is provided as a layer on the bottom surface of the substrate.
18. The device according to claim 13 wherein the diamond layer completely fills the via.
19. The device according to claim 13 wherein the diamond layer only partially fills the via.
20. A semiconductor device comprising:
a substrate including a top surface and a bottom surface, said substrate further including a via formed through the bottom surface and into the substrate, wherein diamond is provided within the via in the substrate;
a plurality of GaN epitaxial layers grown directly on the top surface of the substrate, wherein the via extends completely through the substrate and into at least one of the epitaxial layers; and
a plurality of device layers grown on the epitaxial layers.