Effects of high-temperature anneals on 4H–SiC Implanted with Al or Al and Si

Co-implanting Si into 4H–SiC with Al hinders the ability of the Al acceptors to activate electrically at the lower annealing temperatures, but for annealing temperatures>1600°C, the effect is much less, suggesting that the activation energy for incorporating Al as an acceptor no longer controls the rate-determining step in this process. The cathodoluminescence data indicate that Al acceptors are trapped out by the DI defect, and this effect is more pronounced for the higher annealing temperatures. The increase in χmin with the annealing temperature at the higher temperatures can be explained by the nucleation and growth of structural defects, and the transmission electron miscroscopy results show that these defects are stacking faults. The stacking faults can be described as being quantum dots of different polytypes or domain walls with a point-defect periodic structure between the faulted and unfaulted regions, and they could be the source for the peaks associated with the DI defect. Also, we observed th...