The H-induced Si segregation on 1.4 monolayer Ge-covered (001)Si surfaces, which had been studied by means of Fourier-transform infrared-attenuated total reflectance spectroscopy, was again studied by using X-ray photo-electron diffraction and high-resolution electron energy-loss spectroscopy. It was demonstrated that Ge/Si place exchange already took place, to a limited extent, at room temperature. It was observed that increasing the temperature of H-exposure increased Si surface segregation, which was in turn related to Ge-H decomposition. It was deduced that the creation of free Ge-surface dangling bonds strongly modified the energetic balance at the surface and thereby favoured Si segregation. It was proposed that the driving force for H-induced Si/Ge site exchange was mainly the thermodynamics which were involved in the modification of H populations with temperature.

Thermodynamically Driven Ge/Si Place Exchange Induced by Hydrogen on Ge-Covered Si(001) Surfaces T.Angot, P.Louis: Physical Review B, 2000, 61[11], 7293-6