MICROSTRUCTURE AND COMPOSITION OF AN ANODICALLY ETCHED (111) SI SURFACE

Scanning electron microscopy, transmission electron microscopy and x-r ay photoelectron spectroscopy data for the topmost part of an anodical ly etched (111) p-Si wafer exhibiting bright visible photoluminescence have been analysed with regard to microstructure and chemical composi tion. It is concluded that this region consists of two layers. The fir st topmost layer contains six compounds: Si-[O2H2], SiO2, SiO, Si6O3H6 , Si and SiH. In this layer the silicon species depth profile and temp erature dependence were investigated. We find that Si-[O2H2] and SiH d ecomposed completely at 650 K and at 730 K respectively. The amount of siloxene is independent of temperature up to 650 K and then begins to decrease. This was accomplished with desorption of hydrogen from Si6O 3H6 surface species and irreversible oxidation of the samples.