Laser annealing induced high Ge concentration epitaxial SiGe layer in Si_(1-x)Ge_x virtual substrate

摘要

Graded silicon germanium (Si_(1-y)Ge_y) epilayer with a thin layer of high Ge concentration (～36%) near the surface is obtained by laser thermal annealing (LTA). The graded Si_(1-y)Ge_y layer is formed during a liquid phase regrowth after LTA. The relaxation in this graded Si_(1-y)Ge_y epilayer is insignificant; therefore it can be integrated into the source/drain of the p-type metal-oxide-semiconductor field effect transistor to induce high compressive strain to the Si channel. The thickness of the graded Si_(1-y)Ge_y epilayer and the concentration of the Ge near the surface can be controlled by the laser fluence, which in turn changes the strain induced to the Si channel of strained devices.