Strain relaxation of Si0.75Ge0.25 in hydrogen-implanted Si0.75Ge0.25/B-doped Si0.70Ge0.30/Si heterostructure

Abstract

An approach used to obtain a high-quality strain-relaxed SiGe layer by investigating the preferential aggregation and homogenization of nanometric bubbles along the B-doped Si0.70Ge0.30 interlayer in the H-implanted Si0.75Ge0.25/B-doped Si0.70Ge0.30/Si heterostructure has been proposed. The formation of nanometric bubbles is found to be closely correlated to the B atoms doped in the buried Si0.70Ge0.30 layer. Moreover, with the B-doped ultrathin Si0.70Ge0.30 interlayer, the formed nanometric bubbles can interact with dislocation loops and eject them by gliding to the Si0.70Ge0.30/Si interface. The threading dislocation density is 3.3 × 105 cm−2, which is superior to that of the sample grown with a graded buffer layer.