High resolution photoemission study of the surfactant desorption after Sb mediated Ge epitaxy on Si(001)

The deposition of 3 ML of Ge on Si(001) in the presence of 1 ML of Sb was investigated by core level photoemission spectroscopy. In addition to the predominant localisation of Ge below Sb, revealed by the comparison between a surface-sensitive and a bulk-sensitive detection configuration, the complete lack of surface components in the Ge 3d spectrum indicates the absence of dimerized Ge atoms at the top layer. Ge(2 × 1) surface reconstruction was recovered when desorbing Sb by annealing cycles to 750°C. The possibility to reversibly recover the surface reconstruction when adding and removing an Sb capping layer on Ge/Si(001) indicates that Sb can be successfully used to preserve perfectly terminated SiGe heterostructures against contamination.