A INTRODUCTION

Hall, and C-V, four-point probe and spreading resistance measurements to some extent provide a measure of the net impurity concentration of dopants in SiC ([N _D - N _A] or (N _A - N _D]). In addition, Hall measurements provide a method for obtaining the mobility of the net carriers. These measurements have been applied to both n- and p-type SiC and its various polytypes. In this Datareview, we will report on the mobilities for most of the SiC polytypes under various growth conditions.

The mobility and carrier concentration in SiC are functions of the polytype, growth technique, starting substrate doping conditions and temperature. The information that follows is divided into polytype and the growth technique information is also provided. We do not claim to report on all the known measurements, but a representative number.

B CARRIER MOBILITIES AND CONCENTRATIONS

The electron and hole mobilities in this section are at low field conditions where ? _e = q ?/m _e* and _p = q ?/m _p*, where q is the electronic charge, ? is the average scattering time, m _e* is the electron effective mass and m _p* the hole effective mass. The principal scattering mechanisms controlling the scattering time in SiC are ionized impurity, acoustical phonon, piezoelectric, neutral impurity and polar optical phonon scattering. Under most conditions...