Phosphorus-doped chemical vapor deposition of diamond

The semiconducting properties of phosphorus-doped diamond thin films grown using a metal-chamber-type microwave plasma-assisted chemical vapor deposition system have been investigated by Hall measurements over a wide temperature range. On {111} surfaces of Ib diamond substrates, the n-type conductive diamond thin films showing a mobility over 100 cm(2)/(V s) can be reproducibly obtained under doping conditions of P/C of 500 ppm in the gas phase. The best sample has shown a mobility of 240 cm(2)/(V s) at room temperature. The activation energy of the carrier was about 0.6 eV. Hopping conductivity has not been observed for these samples as a dominant conduction mechanism even at room temperature, as confirmed by temperature-dependent Hall measurements. However, the carrier mobility shows a slow temperature dependence (proportional to similar to T-0.7) even for the best sample; this implies the existence of another scattering mechanism with phonon scattering, which limits the carrier mobility at low temperature. (C) 2000 Elsevier Science S.A. All rights reserved.