Patent ID: 7253455

Claim:
A semiconductor device comprising: a substrate; a buffer layer formed over the substrate; a bottom layer comprising Al x Ga 1−x As formed over the buffer layer, the bottom layer having a first doped region formed therein, wherein the first doped region comprises a layer of GaAs, a layer of Si, and a layer of GaAs; an In x Ga 1−x As layer formed over the bottom layer; an Al x Ga 1−x As layer formed over the In x Ga 1−x As layer, the Al x Ga 1−x As layer having a second doped region formed therein, wherein the second doped region comprises a layer of GaAs, a layer of Si, and a layer of GaAs; an undoped GaAs layer formed over the Al x Ga 1−x As layer, the undoped GaAs layer having a first recess formed therein that exposes a portion of the Al x Ga 1−x As layer; a doped GaAs layer formed over the undoped GaAs layer, the doped GaAs layer having a second recess therein that exposes a portion of the undoped GaAs layer; a control electrode having opposite ends formed within the first recess of the undoped GaAs layer and within the second recess of the doped GaAs layer; and first and second current electrodes disposed on the doped GaAs layer proximate opposite ends of the control electrode such that the doped GaAs layer provides current through the first and second current electrodes for the semiconductor device.