Free electron density and mobility in high-quality 4H-SiC

The free electron density and low-field electron mobility of 4H-SiC is examined in the temperature range 35-900 K. In good samples the electron density is constant in the temperature range 300-900 K, which offers interesting possibilities for high temperature sensor applications. On the best sample an experimental electron mobility of 12 400 cm(2)/V s at 50 K is found. A complete description of the temperature dependence of the electron density and mobility is given. We take into account the effects of the two inequivalent lattice sites as well as the valley-orbit splitting of the ground state at the hexagonal sites. The dependence of room-temperature mobility on electron concentration is established, described theoretically and compared with the results obtained by different authors. (C) 2000 American Institute of Physics. [S0003-6951(00)04650-7].