Photoelectron spectroscopy studies of Tm silicide films on Si(111)

The formation of TmSi2−x on Si(111) by means of solid phase epitaxy has been studied with low‐energy electron diffraction (LEED) and photoelectron spectroscopy (PES). PES shows that metallic TmSi2−x is formed and that the Tm of the silicide is trivalent. It is also found that this Tm silicide has Tm in the surface layer. Very good (√3×√3)R30° patterns were seen in LEED showing that the Tm silicide can be formed epitaxially. The optimum annealing temperature used in order to form the epitaxial TmSi2−x silicide was around 750 °C. When temperatures below 500 °C were used as reaction temperatures, LEED showed diffuse patterns and PES showed that the reacted film consisted of several different types of Tm‐Si compounds.