Effects of Carrier Concentration on Electrical Resistivity of SiC Ceramics with BeO Addition

Abstract

The effects of carrier concentration on the electrical resistivity and electrical barrier height at grain boundaries in SiC ceramics with BeO addition are described. The carrier concentration of the SiC ceramics was controlled by the doping of nitrogen of Si₃N₄ as a donor or aluminum of Al₂O₃ as an acceptor. The barrier height and the electrical resistivity of the SiC ceramics with grains of p-type conduction are higher than those with grains of n-type conduction by 0.3-0.6eV in the barrier height and the factor of 10-10⁵ in the electrical resistivity. In p-type conduction, the barrier height and the electrical resistivity decrease steeply at the carrier concentration above -10¹⁸ cm^-3 in SiC grains. These phenomena are explained by the filling of trapping levels in the grain boundaries with the carriers with increase of the carrier concentration in the SiC grains.