Compound semiconductor device and method of manufacturing the same

1. A compound semiconductor device comprising:

a substrate;

an electron channel layer and an electron supply layer formed over the substrate;

a gate electrode, a source electrode and a drain electrode formed on or above the electron supply layer;

a p-type semiconductor layer formed between the electron supply layer and the gate electrode; and

an n-type semiconductor layer formed a above the electron supply layer, and at least between the gate electrode and the source electrode, and between the gate electrode and the drain electrode,

wherein the p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

wherein the n-type semiconductor layer contains, as an n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer.

2. The compound semiconductor device according to claim 1 , wherein the p-type semiconductor layer is a SiC layer which contains a p-type impurity.

3. The compound semiconductor device according to claim 2 , wherein the SiC layer is in an amorphous state.

4. The compound semiconductor device according to claim 1 , wherein the p-type impurity is Al or Ga.

5. The compound semiconductor device according to claim 1 , wherein the n-type impurity contained in the n-type semiconductor layer is nitrogen (N).

6. The compound semiconductor device according to claim 1 , further comprising a pn-junction diode, which comprises a second p-type semiconductor layer connected to the source electrode and a second n-type semiconductor layer connected to the drain electrode, wherein

the second p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

the second n-type semiconductor layer contains, as an n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer.

7. A power supply apparatus comprising

a compound semiconductor device, which comprises:

a substrate;

an electron channel layer and an electron supply layer formed over the substrate;

a gate electrode, a source electrode and a drain electrode formed on or above the electron supply layer;

a p-type semiconductor layer formed between the electron supply layer and the gate electrode; and

an n-type semiconductor layer formed above the electron supply layer, and at least between the fate electrode and the source electrode, and between the gate electrode and the drain electrode,

wherein the p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

wherein the n-type semiconductor layer contains, as a n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

8. An amplifier comprising

a compound semiconductor device, which comprises:

a substrate;

an electron channel layer and an electron supply layer formed over the substrate;

a gate electrode, a source electrode and a drain electrode formed on or above the electron supply layer; and

a p-type semiconductor layer formed between the electron supply layer and the gate electrode; and

an n-type semiconductor layer formed above the electron supply layer, and at least between the gate electrode and the source electrode, and between the gate electrode and the drain electrode,

wherein the p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

wherein the n-type semiconductor layer contains, as an n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer.

9. A method of manufacturing a compound semiconductor device, comprising:

forming an electron channel layer and an electron supply layer over a substrate;

forming a p-type semiconductor layer above the electron supply layer;

forming a source electrode and a drain electrode on or above the electron supply layer, at positions in planar view placing the p-type semiconductor layer in between;

forming a gate electrode on the p-type semiconductor layer; and

forming an n-type semiconductor layer above the electron supply layer, and at least between the gate electrode and the source electrode, and between the gate electrode and the drain electrode,

wherein the p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

wherein the n-type semiconductor layer contains, as an n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer.

10. The method of manufacturing a compound semiconductor device according to claim 9 , wherein the p-type semiconductor layer is a SiC layer which contains a p-type impurity.

11. The method of manufacturing a compound semiconductor device according to claim 10 , wherein the SiC layer is in an amorphous state.

12. The method of manufacturing a compound semiconductor device according to claim 9 , wherein the p-type impurity is Al or Ga.

13. The method of manufacturing a compound semiconductor device according to claim 9 , wherein the n-type impurity contained in the n-type semiconductor layer is nitrogen (N).

14. The method of manufacturing a compound semiconductor device according to claim 9 , further comprising forming a pn-junction diode, which comprises a second p-type semiconductor layer connected to the source electrode, and a second n-type semiconductor layer connected to the drain electrode, wherein

the second p-type semiconductor layer contains, as a p-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer, and

the second n-type semiconductor layer contains, as an n-type impurity, an element same as that being contained in at least either of the electron channel layer and the electron supply layer.