Elastic electron fine-structure investigation of oxygen interaction with the Si(111) surface

The elastic electron fine-structure (EEFS) technique is applied to the study of the interaction of oxygen with the Si (111) surface and to the formation of the Si—SiOxinterface. The SiOxis in the range of 0–5 monolayers. The Si-Si bond peak in the radius distribution function has a broad shoulder which suggests the existence of a distribution of the Si-Si bond length with a spread of up to 10% with respect to the bulk bond length. When the oxide thickness exceeds ~2 monolayers, the presence of 0–0 bonds is also detected. After high exposure at high temperature, the O-Si bond length appears to have shifted toward a lower value by ~0.1 A. This experiment demonstrates the applicability of the EEFS technique in the submonolayer and monolayer region. The advantages and disadvantages of EEFS over other short-range-order probing techniques are discussed.