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In this letter, we analyze by means of first-principles electronic structure calculations the diffusion of B impurities in 3C-SiC. We find, through molecular dynamics, that substitutional B at a Si lattice site is readily displaced by a nearby Si interstitial by the process known as a kick-out mechanism, in agreement with recent experimental results. This is in contrast to the situation in Si, where B has recently been shown to diffuse via an interstitialcy mechanism.

We report the results of an ab initio study of N and P dopants in SiC. We find that while N substitutes most favorably at a C lattice site, P does so preferably at a Si site, except in n-doping and Si-rich 3C-SiC. Furthermore, we consider a series of dopant complexes that could form in high-dose implantation, in order to investigate the dopant activation behavior in this limit. We find that all N complexes considered lead to passivation through the formation of a deep level. For P, the most stable aggregate is still an active dopant, while passivation is only observed for complexes with a higher formation energy. We discuss how these results could help in the understanding of the observed experimental high-dose doping and codoping behavior of these species.

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Effect of crystal orientation on the implant profile of 60 keV Al into 4H-SiC crystals J. Appl. Phys. 93, 8914 (2003); 10.1063/1.1569972 Low-dose aluminum and boron implants in 4H and 6H silicon carbideA strong channeling effect of Al ϩ ions implanted into crystalline SiC has been observed by Monte Carlo simulations and experiments especially designed to demonstrate this phenomenon have been performed. Depth distributions of implanted Al were measured for on-and controlled off-axis Al implantations using secondary ion mass spectrometry ͑SIMS͒. Much deeper and wider profiles are obtained for the on-axis implantations as compared to off-axis implants. For higher doses, the experiment also reveals the growth of an intermediate peak slightly deeper than the random peak. The origin of the intermediate peak can be understood by combining SIMS results with Monte Carlo simulations, which motivates the development of advanced simulation tools for the ion implantation process in SiC.