Abstract
A method comprises epitaxially growing a gallium nitride (GaN) layer over a silicon substrate, epitaxially growing a donor-supply layer over the GaN layer, and etching a portion of the donor-supply layer. The method also comprises depositing a passivation layer over the donor-supply layer and filling the etched portion of the donor-supply layer, forming a source and a drain on the donor-supply layer, and forming a gate structure between the source and the etched portion of the donor-supply layer. The method further comprises depositing contacts over the gate structure, the source, and the drain.