FORMATION OF UNSTRAINED SI1-XGEX LAYERS BY HIGH-DOSE GE-74 ION-IMPLANTATION IN SIMOX

Single crystalline, strain relieved Si1-xGex layers were fabricated on buried, amorphous SiO2 by high-dose Ge-74 ion implantation into the S i surface layer of SIMOX structures followed by thermal treatment. Ion implantation was performed with energies between 80 and 160 keV and i on doses between 1.5x10(17) and 3x10(17) cm(-2). Rutherford backscatte ring spectrometry, He+ ion channeling and transmission electron micros copy were employed to characterize layer thickness, stoichiometry and crystalline quality of the newly formed Si1-xGex layers. The Ge concen tration x of the resulting Si1-xGex layer can be chosen by using an ap propriate implantation dose. Depending on implantation dose and energy , homogeneous Si1-xGex layers with Ge concentrations between x = 0.13 and 0.29 were obtained. Strain measurements by ion channeling confirme d complete strain relaxation of the Si1-xGex layer after annealing.