Self-diffusion of C12 and C13 in intrinsic 4H–SiC

Abstract

Self-diffusion of carbon (12C and C13) in low-doped (intrinsic) 4H–SiC has been studied using secondary ion mass spectrometry. A two layer C13 enriched structure with C13/12C ratios of 0.01 and 0.1, respectively, have been prepared by vapor phase epitaxy. Subsequent anneals have been carried out in Ar atmosphere in a rf heated furnace between 2100 and 2350 °C for 15 min–40 h. The C13 depth profiles reveal a strict t evolution for the diffusion, and the extracted carbon self-diffusion coefficients closely follow an Arrhenius temperature dependence: D*=8.4×102 exp(−8.50 eV/kT) cm2/s. The extracted D* are found to be 5 orders of magnitude lower than previously reported for the same temperatures in C14 radio-tracer experiments.