Low Leakage Current GaN MIS-HEMT with SiNx Gate Insulator using N-2 Plasma Treatment

Abstract

In this work, an effective N-2 plasma treatment for suppressing leakage current in GaN MIS-HEMT has been demonstrated. We observed an important issue of leakage current from the SiNx/GaN interface. To investigate the leakage current mechanisms, we measured the leakage current from all the possible paths in the device structure, such as gate, mesa isolation, and drain leakage. The current-voltage measurement results reveal a severe leakage path at the SiNx/GaN interface after SiNx deposited on the GaN surface without N-2 plasma treatment. By using N-2 plasma treatment, we succeed in suppressing the leakage current and effectively improve breakdown voltage. A significant performance improvement of GaN MIS-HEMT with very low leakage current has been achieved through the N-2 plasma treatment.