Isolation methods for GaN lateral MOS-channel HEMTs

We have compared two different methods, the shallow recess/field oxide isolation and the mesa isolation, for electrical isolation between GaN lateral MOS-Channel HEMTs. Transistors with these two isolation methods have been fabricated and have been experimentally compared. The off-state leakage current of the devices with linear geometries has been compared with that of the devices with self-enclosed circular geometry, and the difference has been used to characterize the effectiveness of the isolation methods. The leakage current between two adjacent devices has also been measured. The mesa isolation method has been shown to be much more effective in both tests, and the isolation effectiveness has been maintained at elevated temperatures.