Semi-Insulating Polycrystalline Silicon by Low Pressure Chemical Vapour Deposition from Disilane and Nitrous Oxide

Usually, semi-insulating polycrystalline silicon films SiO x are obtained from the chemical decomposition of silane and nitrous oxide. In this paper we describe the study of semi-insulating polycrystalline silicon (SIPOS) films from disilane and nitrous oxide by low pressure chemical vapour deposition. The kinetics of growth and the variation of oxygen content have been investigated relatively to deposition parameters such as temperature, total pressure and gas flow ratio. The oxygen content is assessed by X-ray photoelectron spectroscopy (XPS) and by differential thickness method. We show that the growth rate is higher for “disilane SIPOS films” than “silane SIPOS films” and we explain this behaviour by the strong difference in growth rate of silylene species. We also show that the inhibition effect of nitrous oxide on the growth rate is very low in the case of SIPOS films obtained with disilane. The electrical resistivity depends on the oxygen content and is ranged between 109 and 1013 Ω· cm.