Aluminum free group III-nitride based high electron mobility transistors
View Patent ↗Aluminum free high electron mobility transistors (HEMTs) and methods of fabricating aluminum free HEMTs are provided. In some embodiments, the aluminum free HEMTs include an aluminum free Group III-nitride barrier layer, an aluminum free Group III-nitride channel layer on the barrier layer and an aluminum free Group III-nitride cap layer on the channel layer.
1. A high electron mobility transistor (HEMT), comprising:
an aluminum free Group III-nitride barrier layer;
an aluminum free Group III-nitride channel layer on the barrier layer;
an aluminum free Group III-nitride cap layer on the channel layer; and
a first doped GaN layer between the barrier layer and the channel layer, the first doped GaN layer comprising a Tin (Sn), Oxygen (O) and/or Germanium (Ge) doped GaN layer.
2. The HEMT of claim 1 , wherein the barrier layer comprises a doped Group III-nitride region between the aluminum free Group III-nitride channel layer and a substrate and wherein the barrier layer is doped with iron (Fe).
3. The HEMT of claim 2 , further comprising an undoped Group III-nitride layer disposed between the doped Group III-nitride region and the channel layer.
4. The HEMT of claim 1 , wherein the barrier layer comprises a GaN layer, the channel layer comprises an InGaN layer and the cap layer comprises a GaN layer.
5. The HEMT of claim 4 , wherein the barrier layer has a thickness of from about 3.0 nm to about 1 mm, the channel layer has a thickness of from about 0.3 nm to about 19 nm or from about 21 nm to about 50 nm and the cap layer has a thickness of from about 1 nm to about 19 nm or from about 21 nm to about 100 nm.
6. The HEMT of claim 4 , wherein the InGaN layer has a percentage of indium of from about 1% to about 9% or from about 11% to about 100%.
7. The HEMT of claim 1 , wherein the first doped GaN layer has a thickness of from about 0.2 nm to about 9 nm.
8. The HEMT of claim 1 , wherein the first doped GaN layer has a dopant concentration of from about 1×10 17 cm −3 to about 1×10 ˜ cm −3 or from about 1×10 20 cm −3 to about 1×10 21 cm −3 .
9. The HEMT of claim 1 , further comprising a first undoped GaN layer disposed between the first doped GaN layer and an InGaN channel layer.
10. The HEMT of claim 9 , wherein the first undoped GaN layer has a thickness of from about 0.3 nm to about 4.5 nm or from about 5.5 nm to about 10 nm.
11. The HEMT of claim 1 , wherein the channel layer comprises a doped Group III-nitride region on the aluminum free Group III-nitride barrier layer.
12. The HEMT of claim 11 , wherein the channel layer comprises an InGaN channel layer and the barrier layer comprises a GaN barrier layer, the InGaN channel layer comprising a doped region on the GaN barrier layer.
13. The HEMT of claim 1 , wherein the HEMT further comprises a silicon carbide substrate and wherein the aluminum free Group III-nitride barrier layer is on the silicon carbide substrate.
14. The HEMT of claim 1 , wherein the barrier layer comprises an undoped barrier layer.