Impact of CF4 Plasma Treatment on GaN

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.