High-Field Hole Transport in Strained Si and SiGe by Monte Carlo Simulation:Full Band Versus Analytic Band Models

摘要

Monte Carlo results are presented for the velocity-field characteristics of holes in (i)unstrained Si, (ii) strained Si and (iii) strained SiGe using a full band model as well as ananalytic nonparabolic and anisotropic band structure description. The full band MonteCarlo simulations show a strong enhancement of the drift velocity in strained Si up tointermediate fields, but yield the same saturation velocity as in unstrained Si. The driftvelocity in strained SiGe is also significantly enhanced for low fields while beingsubstantially reduced in the high-field regime. The results of the analytic band modelsagree well with the full band results up to medium field strengths and only the saturationvelocity is significantly underestimated.