Very high hole mobility in p-type Si/SiGe modulation-doped heterostructures

Abstract

In this study, high-quality Si/Si1-xGex/Si p-type modulation-doped heterostructures were grown by ultrahigh-vacuum/chemical vapor deposition (UHV/CVD). High-field magnetotransport measurements revealed Shubnikov-de Hass oscillations in the longitudinal magneto resistance and the integer quantum Hall effect in transverse magnetoresistance illustrating the presence of a well-confined two-dimensional hole gas. The mobilities of the two-dimensional hole gas, as high as 12500 cm(2)/V . s at 0.65 K, were obtained for normal (doped layer at surface side) modulation-doped heterostructures with x = 0.12 at a sheet carrier concentration of 3.45 x 10(11) cm(-2). In addition, for this heterostructure, temperature-dependent measurements of Shubnikov-de Hass oscillations in the range 0.65 K-2.4 K were taken and the hole effective mass of 0.295m(0) + 0.01m(0) was obtained.