Simulation of enhanced interface trapping due to carrier dynamics in warped valence bands in SiGe devices

In the present paper we examine the modelling of a hitherto unidentified interface scattering and trapping/de-trapping effect which is a consequence of the hole dynamics in the warped valence band structures of SiGe MOSFETs. We describe the simulation of this process in detail using classical phase-space analysis and direct space integration. The formation of a quantum vortex in the flow is predicted. A simple quantised version of the model based on Bohr-Sommerfeld quantisation is described which allows us to evaluate the effective parameters of the trapping effect. Although warped valence bands exist in silicon there are basic differences between SiGe layered structures and current Si devices which may mitigate against the effect in silicon.