Calculation of the hole concentration in boron-doped diamond

Calculations of the hole concentration and its activation energy in boron-doped diamond are presented. The detailed structure of the valence band is taken into account by using a temperature-dependent degeneracy factor. The calculations indicate that the customary disregard of the spin-orbit band leads to the overestimation of the compensation ratio. The model developed by Lee and McGill for silicon [J. Appl. Phys. 46, 373 (1975)] is then applied to p-type diamond. The activation energy of the hole concentration is compared with experimental data. When valence-band-edge shift, valence-band-edge tailing and broadening of the acceptor level are concurrently taken into consideration, the decrease in the experimental activation energy observed with increasing boron concentration can be satisfactorily described. The model presented here significantly improves the understanding of the temperature dependence of the hole concentration in boron-doped diamond. (C) 1999 American Institute of Physics. [S0021-8979(99)08803-9].