Ion beam synthesis of n-type doped SiC layers

This work reports the ion beam synthesis of n-doped SiC layers. For this, two approaches have been studied: (i) conventional method of doping by implanting with N+ into an ion beam synthesised SiC layer and (ii) a novel method based on pre-doping (with N+ and P+) of the Si wafers before the ion beam synthesis of SiC. For the N+ implantation the electrical data show a p-type overcompensation of the SiC layers for both doping methods used. The structural (XRD) and in-depth (SIMS, spreading resistance) analysis of the samples suggest this overcompensation to be induced by p-type active defects related to the N+ ion implantation damage, and therefore, the need for further optimisation of their thermal processing. In contrast, the P+-doped SiC layers always show n-type conductivity. This is also accompanied by a higher structural quality, being the spectral features of the layers similar to those from the undoped material. Our electrical data, together with the absence of additional stress related to P-implant suggests that this technique could be suitable to avoid effects related to the ion implantation damage in the SiC lattice, although the electrical activation of P in the SiC lattice is about one order of magnitude lower than in Si.