UC Santa Barbara

We present a systematic study of the impact of CF4 plasma treatment on GaN. It was found that CF4 plasma etches GaN at a slow rate and yields a smooth etched surface. The effect of CF4 plasma on electrical characteristics of GaN metal-semiconductor field-effect-transistor structures shows that the CF4 plasma introduces acceptors into the near surface region of the GaN, which depletes mobile electrons. It was further demonstrated that leakage current of AlGaN/GaN (or GaN) Schottky diodes can be significantly suppressed by proper CF4 plasma treatment. These unique properties of CF4 plasma can be utilized for the advanced processing of GaN transistors.