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

The free electron density and low-field electron mobility of 4H-SiC is exam ined in the temperature range 35-900 K. In good samples the electron densit y 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 c omplete description of the temperature dependence of the electron density a nd mobility is given. We take into account the effects of the two inequival ent lattice sites as well as the valley-orbit splitting of the ground state at the hexagonal sites. The dependence of room-temperature mobility on ele ctron concentration is established, described theoretically and compared wi th the results obtained by different authors. (C) 2000 American Institute o f Physics. [S0003-6951(00)04650-7].