A low energy electron diffraction study of the PH 3 adsorption on the Si (111) surface

Abstract

The reaction of PH 3 with a clean silicon (111) surface was studied by low energy electron diffraction (LEED). A number of diffraction patterns were observed in the temperature range of 25–1000°C using PH 3 pressures of 5 × 10 −8 to 10 −5 Torr. The LEED pattern of one of them, the P-6 √3 structure, could be interpreted by multiple diffraction. The structure appears to be a densely packed phosphorus layer on top of the surface. The activation energy for desorption of the layer was calculated. For the other patterns no structure models could be proposed with certainty. The correlation with adsorption measurements on powders is discussed and the LEED results of reactions of other hydrides with silicon and germanium (111) surfaces are mentioned.