UCLA

Because of the special material properties such as wide band gap, high electron mobility and high breakdown field, Gallium nitride (GaN) based semiconductor devices are well suited for power switching applications. GaN-on-Si technology could significantly reduce the wafer cost of GaN devices. The size of high quality GaN-on-Si wafer is now available up to 6 inch. In order to implement GaN transistors for high-voltage switching applications, there are three core technologies. One is the realization of normally-off operation with low leakage current; the second is the reduction of the on-resistance; the third is increasing the breakdown voltage of the device. Another advantage of GaN based device is the capability to operate at high temperatures. The wide band gap of GaN leads to very low thermal generation of carriers. In this thesis, a field-effect transistor (FET) employing metal-insulator-semiconductor (MIS) structure is proposed to result normally-off operation, temperature-independent threshold voltage and capability of blocking 600V at 200 °C.