Monte Carlo analysis of electron heating in Si/SiO2 superlattices

In this work, we investigate the transport properties of Si/SiO2 superlattices with a multiband one-particle Monte Carlo simulator. Using the envelope function approximation, we solve the Kronig-Penney potential along the growth direction z using a tight-binding-like analytical form; we also consider parabolic dispersion along the xy plane. The scattering mechanisms introduced in the simulator are confined optical phonons, both polar and nonpolar. Owing to the very flat shape of the bands along the growth direction, very low drift velocities are found for vertical transport. However, the simulation shows that, for oblique fields, the transport properties along the vertical direction are strongly influenced by the in-plane component of the electric field: in this way higher vertical drift velocities can be obtained. The results point out that in-plane carrier heating and multiband properties are responsible for this behavior. (C) 2002 Elsevier Science B.V. All rights reserved.