Seminars Archive

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

Abstract
High resolution core level spectroscopy has been used to characterise the Sb-terminated Si(001) and the surfactant role of Sb in Ge/Si(001) epitaxy. On the Sb-1x1 reconstruction were found a very narrow bulk component, indicative of an ideal bulk termination. Two surface components were identified in the Si 2p core level measured on the Sb-2x1 surface at 1ML Sb coverage. Moreover the deposition of 3 ML of Ge on Si(001) in the presence of 1 ML of Sb was investigated. The predominant localisation of Ge below Sb, is revealed the comparing surface-sensitive and 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(2x1) 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.