Patent ID: 7250641

Claim:
A nitride semiconductor device comprising: a silicon substrate; a first aluminum gallium nitride (Al x Ga 1−x N (0≦x≦1)) layer formed as a channel layer on said silicon substrate in an island shape; a second aluminum gallium nitride (Al y Ga 1−y N(0≦y≦1, x<y)) layer formed as a barrier layer of a first conductive type or i-type on said first aluminum gallium nitride layer in said island shape; a gate electrode formed on said second aluminum gallium nitride layer; a drain electrode electrically connected to said second aluminum gallium nitride layer; and a source electrode electrically connected to said second aluminum gallium nitride layer, wherein one semiconductor device is formed of said first aluminum gallium nitride layer and said second aluminum gallium nitride layer in said island shape, said source electrode being formed to surround said gate electrode and said drain electrode and formed on a peripheral portion of said second aluminum gallium nitride layer in said island shape.