Electronic properties of the HF-passivated Si(111) surface during the initial oxidation in air

The electronic properties (surface potential and surface state distribution) of the HF-treated Si(111) surface are investigated by the pulsed surface photovoltage technique during the initial oxidation in air. The HF-treated Si surface is characterized by positive surface charge leading to strong inversion for p-type Si and to accumulation for n-type Si independent of the HF treatment time. A large amount of extrinsic states below midgap is observed on the Si surface after long HF treatment times. During the initial oxidation in air the positive surface charge and the extrinsic states decrease and the electronic properties become more like those known for the thermally oxidized Si/SiO2 interface but generally with a higher density of states.