Abstract
Embodiments of the present invention provide a semiconductor device. The semiconductor device includes a semiconductor substrate. A donor supply layer is placed on the semiconductor substrate. The donor supply layer includes the uppermost surface. A gate structure, a drain, and a source are placed on the donor supply layer. A passivation layer conformally covers the gate structure and the donor supply layer. The gate electrode is placed on the gate structure. An electric field plate is placed on the passivation layer between the gate electrode and the drain. The electric field plate includes a floor edge. The gate electrode includes a first edge near the electric field plate, the electric field plate includes a second edge facing the first edge, and a horizontal distance between the first and second edges is within a range from about 0.05 micrometers to about 0.5 micrometers.