Novel Cap Annealing Process for SiC Crystal Using ECR-Sputtered Carbon Films and ECR Plasma Ashing

A high dose impurity doping process for 4H-SiC crystals has been developed using electron cyclotron resonance (ECR) sputtered carbon cap film and ECR plasma ashing. ECR-sputtered carbon films are newly found crystalline carbon films of which the hardness is comparable to that of diamonds. Since this carbon film showed such a high thermal tolerance that the hardness did not change after 1900oC annealing, this carbon cap film worked well for suppressing roughening during annealing for aluminum-ion implanted 4H-SiC. Cap carbon film can be removed successfully by using high density ECR plasma ashing.