Silicoboron-carbonitride ceramics: A class of high-temperature, dopable electronic materials

The structure and electronic properties of polymer-derived silicoboron-carb onitride ceramics are reported. Structural analysis using radial-distributi on-function formalism showed that the local structure is comprised of Si te trahedra with B, C, and N at the corners. Boron doping of SiCN leads to enh anced p-type conductivity (0.1 Ohm (-1) cm(-1) at room temperature). The co nductivity variation with temperature for both SiCN and SiBCN ceramics show s Mott's variable range hopping behavior in these materials, characteristic of a highly defective semiconductor. The SiBCN ceramic has a low, positive value of thermopower, which is probably due to a compensation mechanism. ( C) 2001 American Institute of Physics.