Pitfalls in the measurement of metal/p-Si contacts: The effect of hydrogen passivation

Chemical etching of Si, used in the preparation of clean, hydrogen-terminated Si surfaces, was found to inject hydrogen—leading to the passivation of acceptors at depths over 0.5 μm. This effect explains the ‘‘high’’ barrier heights, the nonlinear capacitance-voltage plots, and the nonuniform dopant profiles observed for metals deposited on unannealed, etched p-type substrates. Room-temperature metal deposition on atomically clean, well-annealed p-type substrates showed no changes in the active dopant profile, in disagreement with metal-acceptor complex mechanisms recently proposed.