Characterisation of cubic SiC layers VPE grown on Si substrates of different conductivity

Cubic SiC layers grown by VPE on n-type, p-type or semi-insulating Si substrates have been characterized as regards the formation of voids in the Si substrate, namely pyramidal voids and micropipes. The former have been detected in n-type substrates, the latter in p-type and semi-insulating substrates. The total empty volume of the pyramidal voids is higher than that of the micropipes suggesting that the probability of Si out-diffusion is higher in the n-type Si substrates. The results are discussed in terms of the influence of the Fermi level on the diffusivity of the Si atoms and their out-diffusion from the substrate.