Investigation of the subustituional behavior and the electrical activation of implanted P and N impurities in SiC

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1. Activation Process of the implated N impurities in 6H-SiCIn the N concentration range below 2×10^<20>/cm^3, the electrical activation is achieved by annealing at 1200℃. The substitution of the N impurities on Si sublattice sites in SiC is also promoted during the annealing at 1200℃. However, in the N concentration range above 2×10^<20>/cm^3, the number of free electrons activated from N impurities is decreased with the increase of the N concentration. In this regime, it is suggested that the excess implanted N impurities preferably occupy the interstitial sites in SiC rather than the substitutional sites.2. Activation process of the implanted P impurities in 6H-SiCThe activation process of the implanted P impurities in 6H-SiC depends on whether the implanted layer is amorphized by implantation process. In the case of the implantation with the amorphization, the implanted P impurities can occupy the Si sublatties sites while the amorphized implant layer is re-crystallized by annealing even at 1000℃, which leads immediately the electrical activation of the implanted P impurities. However, in the annealing at higher temperature induces the out-diffusion and the redistribution of the implanted P impurities in SiC. On the other hand, in the case of the implantation without the amorphization of the implanted layer using "Hot" implantation technique, the concentration of the P impurities on the Si sublattice sites is increase by increasing the annealing temperature, which results in the increase of the free electron concentration in SiC. However, the obtained free electron concentration of the "Hot" implanted SiC is lower than the case of the amorphized implant layer. It is suggested that a part of the implanted P impurities occupy the interstitial sites in SiC.