US Patent 10079297 Compound semiconductor device

A compound semiconductor device includes a compound semiconductor layer, a gate electrode disposed above the compound semiconductor layer, and source and drain electrodes disposed above the compound semiconductor layer with the gate electrode between the source and drain electrodes, wherein the compound semiconductor layer has a groove in a surface thereof at least between the source electrode and the gate electrode in a region between the source electrode and the drain electrode, the groove gradually deepened toward the source electrode.