Nonlinear resistance of polycrystalline boron-doped diamond films

The i-V characteristics for B-doped diamond (BDD) films on Si and quartz ex hibit linear and nonlinear features from four-point probe measurements at v arying currents depending on boron doping. Films with boron concentrations >10(19) cm(-3) have linear characteristics; those with <10(19) cm(-3) have correspondingly increasing nonlinear symmetrical resistance. The value of r esistance extrapolated to zero current is consistent with the literature va lues for BDD films on quartz. The diamond films on Si have lower resistance by leakage through the Si substrate, but also show the nonlinear effect. S uch symmetrical nonlinearity can be explained by potential barriers forming at the grain-grain interfaces, which strongly suppress the flow of majorit y carriers. (C) 1998 The Electrochemical Society. S1099-0062(98)06-109-4. A ll rights reserved.