Reduction of secondary defect density by C and B implants in GexSi1−x layers formed by high dose Ge implantation in (100) Si

Abstract

(100) oriented Si substrates were implanted with 70 keV Ge ions at a dose of 3×1016 cm−2, corresponding to a Ge peak concentration of ≊15 at. %. Annealing at 1100 °C for 10 s forms a large density of secondary defects (dislocation loops). A 30 keV C implant at a dose of 3×1015 cm−2 on the Ge implanted samples suppresses the formation of secondary defects after the annealing. In GexSi1−x layers implanted with 30 keV B at a dose of 2.5×1015 cm−2, a dense dislocation network after annealing is present. Therefore C is much more effective in the suppression of secondary defects than B. In addition, it is shown that good epitaxial quality can be obtained in the heavily B doped GexSi1−x layers amorphizing a 2 μm thick surface layer by high energy Si implants prior to annealing.