Compound semiconductor device and method of manufacturing the same

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 first p-type semiconductor layer formed between the electron supply layer and the gate electrode;
• and
• a second p-type semiconductor layer formed between the electron supply layer and at least one of the source electrode and the drain electrode,
• wherein the one of the source electrode and the drain electrode on the second p-type semiconductor layer comprises:
• a first metal film;
• and
• a second metal film which contacts the first metal film on the gate electrode side of the first metal film, and a resistance of which is higher than that of the first metal film.

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;
• a first p-type semiconductor layer formed between the electron supply layer and the gate electrode;
• and
• a second p-type semiconductor layer formed between the electron supply layer and at least one of the source electrode and the drain electrode,
• wherein the one of the source electrode and the drain electrode on the second p-type semiconductor layer comprises:
• a first metal film;
• and
• a second metal film which contacts the first metal film on the gate electrode side of the first metal film, and a resistance of which is higher than that of the first metal film.

A method of manufacturing a compound semiconductor device, comprising:

• forming an electron channel layer and an electron supply layer over the substrate;
• forming a first p-type semiconductor layer and a second p-type semiconductor layer on or above the electron supply layer;
• forming a gate electrode, a source electrode and a drain electrode on or above the electron supply layer, wherein
• the gate electrode is formed above the first p-type semiconductor layer,
• at least one of the source electrode and the drain electrode is formed on the second p-type semiconductor layer, and
• the forming the gate electrode, the source electrode and the drain electrode comprises:
• forming a first metal film;
• and
• forming a second metal film which contacts the first metal film on the gate electrode side of the first metal film, and a resistance of which is higher than that of the first metal film, the first metal film and the second film being in the one of the source electrode and the drain electrode on the second p-type semiconductor layer.