Patent ID: 8890212

Claim:
A normally-off high electron mobility transistor (HEMT) comprising: a channel layer including a first nitride semiconductor; a channel supply layer on the channel layer, the channel supply layer including a second nitride semiconductor, the channel supply layer configured to induce a two-dimensional electron gas (2DEG) in the channel layer; a source electrode and a drain electrode at sides of the channel supply layer; a depletion-forming layer on the channel supply layer, the depletion-forming layer configured to form a depletion region in at least a partial region of the 2DEG, the depletion-forming layer having at least two thicknesses; a gate insulation layer on the depletion-forming layer; and a gate electrode on the gate insulation layer, the gate electrode contacting the depletion-forming layer, wherein the gate insulation layer defines an opening that exposes a top surface of the depletion-forming layer, and the gate electrode contacts the top surface of the depletion-forming layer through the opening.