Diffusion of Transition Metals in 4H-SiC and Trials of Impurity Gettering

The diffusion of transition metals in 4H-SiC has been investigated by secondary ion mass spectrometry using epilayers and substrates implanted with titanium (Ti), chromium (Cr), iron (Fe), or nickel (Ni). Implanted Cr, Fe, and Ni atoms diffuse by subsequent Ar annealing at 1780 °C in n-type 4H-SiC epilayers. In n + -type substrates, the diffusivities of Ti, Cr, and Fe are almost negligible, while only Ni diffuses. By the helium implantation following the implantation of transition metals, no diffusion of Ti, Cr and Fe is observed in epilayers. The diffusion of transition metals in SiC is discussed based on the results of first-principles calculation.