HEMT and method of fabricating the same
A high electron mobility transistor includes a substrate. A channel layer is disposed on the substrate. An active layer is disposed on the channel layer. The active layer includes a P-type aluminum gallium nitride layer. A P-type gallium nitride gate is disposed on the active layer. A source electrode and a drain electrode are disposed on the active layer.
1. A high electron mobility transistor (HEMT), comprising:
a substrate;
a channel layer disposed on the substrate;
an active layer disposed on the channel layer, wherein the active layer is a P-type aluminum gallium nitride layer;
a P-type gallium nitride gate disposed on the active layer, wherein a concentration of P-type dopants within the P-type gallium nitride gate, within the active layer and within the channel layer decreases from the P-type gallium nitride gate toward the channel layer in a stepwise manner, and among an entirety of the P-type aluminum gallium nitride layer, a concentration of P-type dopants in the P-type aluminum gallium nitride layer which is closer to the channel layer is less than the concentration of P-type dopants in the P-type aluminum gallium nitride layer which is farther from the channel layer; and
a source electrode and a drain electrode disposed on the active layer.
2. The HEMT of claim 1 , wherein the P-type aluminum gallium nitride layer contacts the channel layer.
3. The HEMT of claim 1 , wherein the concentration of P-type dopants within the P-type aluminum gallium nitride layer is between 1E16 atoms/cm 3 and 1E19 atoms/cm 3 .
4. The HEMT of claim 1 , wherein the concentration of P-type dopants within the P-type aluminum gallium nitride layer is 6% to 12% of a concentration of P-type dopants within the P-type gallium nitride gate.
5. The HEMT of claim 1 , wherein P-type dopants within the P-type aluminum gallium nitride layer comprise C, Mg, Zn or Fe.
6. The HEMT of claim 1 , wherein the stepwise manner comprises a plurality of steps, and the steps constitute a stair going down from the P-type gallium nitride gate to the channel layer.
7. A high electron mobility transistor (HEMT), comprising:
a substrate;
a channel layer disposed on the substrate;
an active layer disposed on the channel layer, wherein the active layer is a P-type aluminum gallium nitride layer;
a P-type gallium nitride gate disposed on the active layer, wherein a concentration of P-type dopants within the P-type gallium nitride gate, within the active layer and within the channel layer decreases from the P-type gallium nitride gate toward the channel layer in a stepwise manner, and the channel layer, the active layer and the P-type gallium nitride gate are stacked from bottom to top in a listed sequence, and wherein among an entirety of the P-type aluminum gallium nitride layer, a concentration of P-type dopants in the P-type aluminum gallium nitride layer which is closer to the channel layer is less than the concentration of P-type dopants in the P-type aluminum gallium nitride layer which is farther from the channel layer; and
a source electrode and a drain electrode disposed on the active layer.
8. The HEMT of claim 7 , wherein the P-type aluminum gallium nitride layer contacts the channel layer.
9. The HEMT of claim 7 , wherein the concentration of P-type dopants within the P-type aluminum gallium nitride layer is between 1E16 atoms/cm 3 and 1E19 atoms/cm 3 .
10. The HEMT of claim 7 , wherein the concentration of P-type dopants within the P-type aluminum gallium nitride layer is 6% to 12% of a concentration of P-type dopants within the P-type gallium nitride gate.
11. The HEMT of claim 7 , wherein P-type dopants within the P-type aluminum gallium nitride layer comprise C, Mg, Zn or Fe.