Enhancing the performance of AlGaN/GaN schottky barrier diodes by SF₆ plasma treatment and deep anode recess

In this work, low turn-on voltage (V_on), low leakage current (IR) and high breakdown voltage (VBR) AlGaN/GaN Schottky barrier diodes (SBDs) are fabricated on 6-inch Silicon substrates using an anode recess process combined with SF₆ plasma treatment. Using this process, turn-on voltage is reduced from 1.3 V to 0.6 V, compared to the planar untreated devices due to the reduction of Schottky barrier height by having the Schottky metal in contact with the two dimensional electron gas at the AlGaN/GaN interface. Meanwhile, the V_BR is increased from 400 V to 455 V due to the presence of plasma implanted fluorine ions near the anode. This process also results in a smaller device capacitance, which leads to the reduction of reverse recovery time from 12.9∼14.4 ns to 9.6∼10.7 ns.