High electron mobility transistor device having an aluminum-doped buffer layer
A high electron mobility transistor (HEMT) device is disclosed. The HEMT device includes a substrate with epitaxial layers over the substrate that includes a buffer layer having a dopant comprising aluminum, wherein the concentration of aluminum within the buffer layer is between 0.5% and 3%. The epitaxial layer further includes a channel layer over the buffer layer and a barrier layer over the channel layer. A gate contact is disposed on a surface of the epitaxial layers. A source contact and a drain contact are also disposed on the surface of the epitaxial layers, wherein the source contact and the drain contact are spaced apart from the gate contact and each other.
1 . A high electron mobility transistor (HEMT) device comprising:
a nonlayered substrate;
epitaxial layers over the nonlayered substrate and comprising;
a buffer layer disposed directly on a surface of the nonlayered substrate and having a dopant comprising aluminum that forms aluminum-oxygen complexes within the buffer layer;
a channel layer over the buffer layer;
a barrier layer over the channel layer;
a gate contact disposed on a surface of the epitaxial layers;
a source contact disposed over the surface of the epitaxial layers;
a drain contact disposed on the surface of the epitaxial layers, wherein the source contact and the drain contact are spaced apart from the gate contact and each other; and
wherein the buffer layer comprises gallium nitride.
2 . The HEMT device of claim 1 wherein the concentration of aluminum within the buffer layer is between 0.5% and 0.75%.
3 . The HEMT device of claim 1 wherein the concentration of aluminum within the buffer layer is between 0.75% and 1.25%.
4 . The HEMT device of claim 1 wherein the concentration of aluminum within the buffer layer is between 1.25% and 2%.
5 . The HEMT device of claim 1 wherein the concentration of aluminum within the buffer layer is between 2% and 3%.
6 . The HEMT device of claim 1 wherein the buffer layer is laterally divided into a doped region having the dopant comprising aluminum and an undoped region.
7 . The HEMT device of claim 6 wherein the concentration of aluminum within the doped region is between 0.5% and 0.75%.
8 . The HEMT device of claim 6 wherein the concentration of aluminum within the doped region is between 0.75% and 1.25%.
9 . The HEMT device of claim 6 wherein the concentration of aluminum within the doped region is between 1.25% and 2%.
10 . The HEMT device of claim 6 wherein the concentration of aluminum within the doped region is between 2% and 3%.
11 . A method of fabricating a high electron mobility transistor (HEMT) device having a nonlayered substrate, method comprising:
forming epitaxial layers over the nonlayered substrate comprising steps of:
disposing a buffer layer directly on a surface of the nonlayered substrate, the buffer layer having a dopant comprising aluminum that forms aluminum-oxygen complexes within the buffer layer;
disposing a channel layer over the buffer layer;
disposing a barrier layer over the channel layer;
forming a gate contact on a surface of the epitaxial layers;
forming a source contact over the surface of the epitaxial layers;
forming a drain contact over the surface of the epitaxial layers, wherein the source contact and the drain contact are spaced apart from the gate contact and each other; and
wherein the buffer layer comprises gallium nitride.
12 . The method of claim 11 wherein the concentration of aluminum within the buffer layer is between 0.5% and 3%.
13 . The method of claim 11 wherein the concentration of aluminum within the buffer layer is between 0.5% and 0.75%.
14 . The method of claim 11 wherein the concentration of aluminum within the buffer layer is between 0.75% and 1.25%.
15 . The method of claim 11 wherein the concentration of aluminum within the buffer layer is between 1.25% and 2%.
16 . The method of claim 11 wherein the concentration of aluminum within the buffer layer is between 2% and 3%.
17 . The method of claim 11 further comprising laterally dividing the buffer layer into a doped region having the dopant comprising aluminum and an undoped region.
18 . The method of claim 17 wherein the concentration of aluminum within the doped region is between 0.5% and 0.75%.
19 . The method of claim 17 wherein the concentration of aluminum within the doped region is between 0.75% and 1.25%.
20 . The method of claim 17 wherein the concentration of aluminum within the doped region is between 1.25% and 2%.
21 . The method of claim 17 wherein the concentration of aluminum within the doped region is between 2% and 3%.