Effects of photowashing treatment on gate leakage current of GaAs metal-semiconductor field-effect transistors

Effects of photowashing treatment on gate leakage current (I-GD) of a GaAs metal-semiconductor field-effect transistor were studied by observing changes in atomic composition and band bending at the surface of GaAs through X-ray photoemission spectroscopy. The photowashing treatment produces Ga2O3 on the surface of GaAs, leaving acceptor-type Ga antisites behind under the oxide. The Ga antisites played a role in reducing the maximum electric field at the drain edge of the gate, leading to the decrease of I-GD. The longer photowashing time produced thicker oxide on the surface of GaAs, acting as a conducting pass for electrons, leading to the increase of I-GD.