Investigation of Surface Morphology of 6H-SiC Irradiated with He+ and H2+ Ions

Light ion implantation is one of the important procedures of smart cut for SiC-based semiconductor fabrication. This work investigated the surface morphologies and microstructures of single crystal 6H-SiC irradiated by one or both of H-2(+) and He+ ions at room temperature and then annealed at specific temperatures. Blisters evolved from the coalescence of H nanocracks were formed in the H-2(+) and He++H-2(+) irradiated sample surface, while circular ripples originated from the pressure release of helium bubbles after high temperature annealing were formed in the He+ irradiated sample surface. The lateral radius a of the blisters in the irradiated sample with low H-2(+) fluence was larger than that in the irradiated sample with high H-2(+) fluence and with He++H-2(+) ions. About 8-58% of implanted H atoms contributed to the formation of the blisters. Compared with other irradiated samples, the ratio of w(0)/a and the density of the blisters in the He++H-2(+) irradiated samples were largest. The stress field of the blisters was simulated using finite element method and the inner pressure in the blisters was also calculated. The corresponding mechanism was analyzed and discussed.