EVOLUTION OF THE IN OXIDE SI(111) INTERFACE - ANALYSIS BY ELECTRON SPECTROSCOPIES

The growth of thin In oxide layers on Si(111) substrate surfaces by re active evaporation of In in oxygen atmosphere and the formation of the In oxide-Si interface under ultrahigh-vacuum conditions has been stud ied by Auger electron spectroscopy, electron-energy-loss spectroscoPY, photoemission with use of synchrotron radiation, and inverse photoemi ssion. Oxygen pressure and substrate temperature were varied as the pa rameters of the reactive evaporation. The combined electron spectrosco pic results indicate that for In deposition onto room-temperature subs trate surfaces and P(O2) < 5 x 10(-5) mbar the interfacial layer conta ins metallic In and oxidized Si, but that for higher P(O2) the metalli c In concentration at the interface is reduced. The oxidation of In ap pears to be enhanced away from the In-Si interface, and for P(O2) > 5 X 10(-5) mbar the oxide stoichiometry approaches that of In2O3. At ele vated substrate temperature (250-degrees-C) the growth rate of In oxid e layers is reduced as compared to room temperature, but the oxidation yield at the interface is enhanced. For P(O2) = 2 x 10(-4) mbar and 2 50-degrees-C substrate temperature the growth of a uniform near-stoich iometric In oxide layer is indicated.