Patent ID: 8420421

Claim:
A method for fabricating a GaN-based thin film transistor, comprising: forming a semiconductor epitaxial layer on a substrate, the semiconductor epitaxial layer having a n-type GaN-based semiconductor material; forming an insulating layer on the semiconductor epitaxial layer; forming an ion implanting mask on the insulating layer, the ion implanting mask having an opening to partially expose the insulating layer; ion-implanting a p-type impurity through the opening and the insulating layer to forma p-doped region in the n-type GaN-based semiconductor material, followed by removing the insulating layer and the ion implanting mask; forming a dielectric layer on the semiconductor epitaxial layer; partially removing the dielectric layer so that two portions of the semiconductor epitaxial layer that are located on two opposite sides of the p-doped region are exposed from the dielectric layer; forming source and drain electrodes respectively on the two portions of the semiconductor epitaxial layer; and forming a gate electrode on a remaining portion of the dielectric layer.