Patent ID: 7400001

Claim:
A hetero-junction field effect transistor, comprising: a high resistance nitride semiconductor layer formed on a substrate; an Al-doped GaN layer formed on the high resistance nitride semiconductor layer and having an Al content of 0.3˜0.6 mol %; an undoped GaN layer formed on the Al-doped GaN layer; and an AlGaN layer formed on the undoped GaN layer such that a two-dimensional electron gas (2DEG) layer is formed at an interface between the AlGaN layer and the undoped GaN layer; wherein the undoped GaN layer has a thickness of 0.1˜1 μm; and the Al-doped GaN layer has a thickness of 0.1˜1 μm; said hetero-junction field effect transistor further comprising at least one pair of another Al-doped GaN layer and another undoped GaN layer sequentially formed between the Al-doped GaN layer and the high resistance nitride semiconductor layer.