Patent ID: 9048302
Filing Date: 2015-06-02
Classification: H01L

Abstract:
1. A field effect transistor, comprising: a substrate; a lower semiconductor layer of nitride-based compound semiconductor formed on the substrate; a semiconductor operating layer of nitride-based compound semiconductor formed on the lower semiconductor layer and having a recess, the semiconductor operating layer comprising a carrier drifting layer formed on the lower semiconductor layer and a carrier supplying layer formed on the carrier drifting layer, the carrier supplying layer having a band gap energy greater than that of the carrier drifting layer; an insulating layer formed on the semiconductor operating layer and contacting the lower semiconductor layer at a bottom of the recess; a gate electrode formed on the insulating layer at the recess; and a source electrode and a drain electrode formed on the same surface of the semiconductor operating layer and electrically connected to the semiconductor operating layer with the recess in between the source electrode and the drain electrode, wherein a side wall of the recess at a side of the drain electrode ascends at an angle of θ1 from a top surface of the lower semiconductor layer, a side wall of the recess at a side of the source electrode ascends vertically or at an angle of θ2 from the top surface of the lower semiconductor layer, and the angle θ1 is different from the angle θ2.