Effects of hydrogen treatment on strain relaxation of SiGe epi-layer on Ge substrate

Effects of hydrogen treatment on post-growth strain relaxation of GeSi epitaxial films on Ge substrate were studied. We found that pre-hydrogen treatment at room temperature enhanced strain relaxation during subsequent thermal treatment. We also confirmed that the relaxation enhancement effect became small as the annealing time was elongated and the temperature was raised. These results mean that the effect is more remarkable in the early stage of relaxation. In order to investigate the mechanism of this effect, threading dislocation velocity was measured. However, it was not enhanced by pre-hydrogenation. This fact strongly suggests that the relaxation enhancement effect was caused by increase of dislocation sources, which are attributed to hydrogen atoms incorporated into GeSi film.