Compressive strain dependence of hole mobility in strained Ge channels

Abstract

The strain dependence of the hole mobility was systematically investigated in the compressively strained Ge channel modulation-doped structure. It was clearly observed that the mobility increases with increasing compressive strain until the strain as high as 1.9%. The highest mobility of 20 800 and 2000cm2∕Vs at 8 K and room temperature, respectively, was obtained for the Ge channel structure grown on the relaxed SiGe buffer layers with Ge composition of 53%. The origins of this mobility increase are speculated to be the reduction of effective mass, suppression of interband phonon scattering, and the increased confinement of the holes in the channel layer.