Surface roughness of SixGe1-x layers obtained by high dose Ge implants in Si after oxidation treatments

SixGe1-x layers were obtained by high dose Ge implants in (100) silicon substrates and solid phase epitaxy. Wet cleaning treatments (H2SO4/H2O2) based on silicon surface oxidation greatly increase surface roughness. The thin oxide layer formed on the SixGe1-x layer is essentially composed by SiO2 while no GeO2 has been detected Furthermore, Rutherford backscattering spectrometry reveals Ge segregation at SiO2/SixGe1-x interface. These effects are compared with those produced by the growth of a thicker (15 nm) thermal oxide. The observed phenomena suggest that great care must be used in SixGe1-x surface cleaning treatments.