シリコン単結晶の成長中における点欠陥の拡散挙動

抄録

It is well-known that the type of grown-in defect in single crystals of silicon depends on the ratio of v/G_o (v;growth rate, G_o;axial temperature gradient of the crystal) and that the vacancy-type defect appears above a critical v/G_o, and the self-interstitial type defect appears below this critical ratio. In order to explain the defect behavior by solving the diffusion equations of point defects, it is necessary to know the values of diffusion coefficients and equilibrium concentrations of them. However, the reported values of these quantities scatter widely. We have investigated the necessary conditions which are able to explain the defect behavior. It is shown that the necessary conditions are as follows. 1) D_<v,mp>E_v^f>D_<I,mp> E_I,^f, 2)D_<V,mp>×E_v^f>6×10^<-4> eV・cm^2/sec, 3) E_V^m>E_I^m, E_V^f>E_I^f, 4) The contribution of pair annihilation to the point defects concentration is small near the melting temperature. Where D_<v,mp>,D_<Imp>, diffusion coefficients at melting temperature, E^f, formation energy, E^m; activation energy of diffusion, V and I; vacancies and self interstitials.