Different nonlinear conduction mechanism between α-SiC and β-SiC

Abstract

The nonlinear electrical conductivity of /spl beta/-SiC and /spl alpha/-SiC was investigated. /spl beta/-SiC has an excellent nonlinear electrical conductivity when the particle size varies from 14/spl sim/21 /spl mu/m. Compared with /spl alpha/-SiC, the parallel particle size /spl beta/-SiC micro-powder has lower resistance and greater nonlinear electrical conduction coefficient which is marked by /spl beta/. The difference of electrical conductivity between /spl beta/-SiC and /spl alpha/-SiC is interpreted from the crystal structure and shape. It is shown that the cubic crystal structure /spl beta/-SiC has smaller contact area than hexagonal /spl alpha/-SiC with induced higher contact potential barrier. Under high voltage, the electrical conduction mechanism of the tetrahedral parallel configuration /spl beta/-SiC crystal is more complex than the anti-parallel configuration /spl alpha/-SiC crystal.