Patent ID: 8193566

Claim:
A semiconductor device comprising: a compound semiconductor substrate; a buffer layer, a channel layer, and a Schottky junction forming layer sequentially laminated on said compound semiconductor substrate, each of said buffer layer, said channel layer, and said Schottky junction forming layer being compound semiconductor materials; a source electrode and a drain electrode, each of said source electrode and the drain electrode being disposed on said Schottky junction forming layer; and a gate electrode disposed between said source and drain electrodes and forming a Schottky junction with said Schottky junction forming layer, wherein said channel layer has a dopant impurity concentration that varies with distance from a top surface of said channel layer and is inversely proportional to the third power of distance into said channel layer from said top surface of said channel layer, and said gate electrode has a gate length in a range from 0.2 μm to 0.6 μm.