The effects of the time-dependent and exposure time to air on Au epilayer n-Si Schottky diodes

A study on Au/n-Si Schottky barrier diodes (SBDs) parameters with and witho ut thin native oxide layer fabricated on n-type Si grown by LPE (Liquid-Pha se Epitaxy) technique has been made. The native oxide layer with different thicknesses on chemically cleaned Si surface was obtained by exposing the S i surfaces to clean room air before metal evaporation. The native oxide thi cknesses of samples D2, D3, D4 and D5 are in the form D2 < D3 < D4 less tha n or equal to D5 depending on the exposing time. Id has been seen that the value of the barrier height Phi(b) Of samples D2 (0.64 eV), D3 (0.66 eV), D 4 (0.69 eV) and D5 (0.69 eV) increases with increasing the exposure time an ti tends to that of the initial sample D1 (the initial sample, 0.74 eV), an d thus also their I - V curves. Especially, the experimental results relate d to the exposure time of the surfaces to clean air are close in agreement with recently results reported for the HF-treated n-Si surface during initi al oxidation in air. Furthermore, it has been determined experimentally tha t ageing of the Au contacts on the oxidized epilayer Si leads to barrier he ight values close to those measured for Au on chemically cleaned surfaces.