Interaction of oxygen with Na-covered Si(100)

Abstract

Oxygen interaction with Na-dosed Si(100) has been studied by thermal desorption (TD), Auger electron spectroscopy (AES), electron energy loss spectroscopy (EELS), LEED and work function (Δφ) measurements. It is found that Na-dosing increases drastically the oxygen uptake rate. However, no Na-promoted oxidation of Si(100) occurs with Na in the first layer. Oxidation of Si(100) is observed only for a multilayer Na structure. Linear enhancement of the Si oxidation activity with increasing Na coverage, θ Na, is obtained for θ Na > 0.5. The inhomogeneous oxidation of Si(100) is associated with the formation of NaO 2 3D clusters.