High Performance Normally-Off AlGaN/GaN MIS-HEMT Using Charge Storage Technique

GaN HEMT is an ideal device for power switching applications. However, owing to the false turn-on issue and the requirements for fail-safe operation for the device to be used for electrical vehicles application, a high threshold voltage normally-off GaN HEMT is desired. One of the methods to realize the normally-off operation is to use a charge storage layer under the gate region. However, the magnitude of threshold voltage shift is limited by the charge storage capability of the gate dielectric layer.