SURFACE ELECTRONIC STATES OF LOW-TEMPERATURE H-PLASMA CLEANED SI(100)

The surface of low-temperature H-plasma cleaned Si(100) was studied by angle-resolved UV photoemission spectroscopy. The cleaning process involved an ex situ wet chemical preclean followed by an in situ H-plasma exposure at a substrate temperature of 300-degrees-C. After the in situ H-plasma exposure, a 2 x 1 ordered surface was obtained which exhibited two hydrogen-induced surface states/resonances in the UV photoemission spectra. The temperature dependence of the spectra showed that the Si-H monohydride started to dissociate at a temperature below 500-degrees-C, and the dangling-bond surface states were identified. The spectroscopic properties of the low-temperature H-plasma surface were essentially identical to surfaces prepared by ultrahigh vacuum high-temperature annealing followed by H passivation.