Analysis of high-field hole transport characteristics in Si1−xGex alloys with a bond orbital band structure

We present an analysis of high-field hole transport in strained Si1−xGex alloys using a Monte Carlo technique. A bond orbital model is employed to calculate the valence-band structure in the simulation so that the transport behavior of high-energy holes can be described accurately. The model combines the k⋅p and the tight binding methods and contains no fitting parameters. The spin–orbit interaction and lattice-mismatch-induced biaxial compressive strain are included in the model. The steady-state hole drift velocity and the impact ionization rate are calculated as a function of an electric field up to 500 kV/cm. Good agreement between experiment and simulation is obtained.