Wave function-dependent mobility and suppression of interface roughness scattering in a strained SiGe p-channel field-effect structure

The 4 K Hall mobility has been measured in a top-gated, inverted, modulation-doped Si/Si0.8Ge0.2 structure having a Si:B doping layer beneath the alloy. From comparisons with theoretical calculations, we argue that, unlike an ordinary enhancement-mode SiGe p-channel metal-oxide-semiconductor structure, this configuration leads to a decrease of interface roughness scattering with increasing sheet carrier density. We also speculate on the nature of the interface charge observed in these structures at low temperature. (C) 2000 American Institute of Physics. [S0003-6951(00)01518-7]