Thickness-dependent stress-relaxation in thin SGOI structures and its improvement

The oxidation-induced Ge condensation process of SiGe/Si on insulator structures has been investigated. The relaxation rate obtained in the SiGe layers on insulator (SGOI) abruptly decreased with decreasing SGOI thickness below 50 nm. In order to enhance the relaxation rate in the ultra-thin SGOI, the new technique combined with H+ irradiation with a medium dose (5 × 1015 cm− 2) and post-annealing (1200 °C) has been developed. It was demonstrated that the highly relaxed (70%) ultra-thin SGOI with a low defect density (8 × 106 cm− 2) has been realized by this technique.