Impact of SiN capping during Ohmic Annealing on Performance of GaN-based MISHEMTs

We investigated the effect of SiN capping of the AlGaN surface during ohmic annealing process on the performance of AlGaN/GaN HEMTs. In comparison with the devices without any capping, devices with SiN capping exhibited small variation in threshold voltage from sample to sample with smaller hysteresis of transfer curves. It was verified that the SiN cap during ohmic annealing is effective in reducing threshold voltage instabilities in AlGaN/GaN MIS-HEMTs.