Semiconductor device

A semiconductor device comprising:

• a channel layer;
• a barrier layer above the channel layer and comprising a material having an energy band gap that is different from an energy band gap of the channel layer;
• a gate semiconductor layer above the barrier layer;
• a protection layer on the barrier layer and the gate semiconductor layer;
• a source electrode on a first side of the channel layer and a first side of the barrier layer;
• and
• a drain electrode on a second side of the channel layer and a second side of the barrier layer,
• wherein the protection layer comprises:
• a first protection layer above the barrier layer and comprising a first element;
• and
• a second protection layer above the first protection layer and comprising the first element and a second element different from the first element, and
• wherein a ratio of the first element of the first protection layer increases in a direction away from an upper surface of the barrier layer.

A semiconductor device comprising:

• a substrate;
• a channel layer on the substrate and comprising GaN;
• a barrier layer above the channel layer and comprising AlGaN;
• a gate electrode above the barrier layer and comprising a metal material;
• a gate semiconductor layer between the barrier layer and the gate electrode and comprising GaN doped with a P-type impurity;
• a source electrode on a first side of the gate electrode, and on a first side of the channel layer and a first side of the barrier layer;
• a drain electrode on a second side of the gate electrode, opposite to the first side, and on a second side of the channel layer and a second side of the barrier layer;
• a field dispersion layer on the gate electrode, the field dispersion layer in a same layer as a layer of the source electrode and formed integrally with the source electrode;
• and
• a protection layer between the barrier layer and the field dispersion layer,
• wherein the protection layer comprises:
• a first protection layer on the barrier layer and comprising Si;
• and
• a second protection layer on the first protection layer and comprising SiON, and
• wherein an Si ratio of the first protection layer increases in a direction away from an upper surface of the barrier layer.