Patent ID: 7842972

Claim:
A pseudormorphic˜high-electron-mobility-transistor (PHEMT), comprising: a substrate; a low-temperature-grown (LTG) GaAs gate-insulator layer disposed on the substrate wherein said LTG GaAs gate-insulator-layer has thickness in the range of approximately 200A and 1000A; a gate electrode disposed on the LTG GaAs gate-insulator layer; a channel layer disposed between the substrate and the LTG GaAs gate-insulator-layer; a first spacer layer disposed between a GaAs layer and the LTG GaAs gate-insulator layer; the GaAs layer disposed between the channel layer and the LTG GaAs gate-insulator layer wherein said GaAs layer is doped with silicon and has a thickness in the range of approximately 100A to 500A; wherein the first spacer layer comprises an AlAs layer having a thickness in the range of approximately 25A to 100A; and further comprising a: LTG GaAs buffer layer disposed between the substrate and the channel layer; and wherein the LTG GaAs buffer layer has a thickness in the range of approximately 0.5 um to 1.0 um, and further comprising a second spacer layer disposed between the LTG GaAs buffer layer and the channel layer; and wherein the second spacer layer comprises: an AlAs layer; an AlGaAs layer; and a super lattice layer disposed between the AlAs and AlGaAs layers; wherein the AlAs layer is doped with silicon and has a thickness of approximately 100A; the super lattice layer comprises a GaAs/AlGaAs layer having a thickness in the range of approximately 200A to 800A; the AlGaAs layer is doped with silicon and has a thickness of approximately 50A.