VERY HIGH 2-DIMENSIONAL HOLE GAS MOBILITIES IN STRAINED SILICON-GERMANIUM

We report on the growth by solid source MBE and characterization of remote doped Si/SiGe/Si two-dimensional hole gas structures. It has been found that by reducing the Ge composition to less-than-or-equal-to 13% and limiting the thickness of the alloy layer, growth temperatures can be increased up to 950-degrees-C for these structures while maintaining good structural integrity and planar interfaces. Record mobilities of 19 820 cm2 V-1 s-1 at 7 K were obtained in normal structures. Our calculations suggest that alloy scattering is not important in these structures and that interface roughness and interface charge scattering limit the low temperature mobilities.