Studies were made of diffusion in material with high donor concentrations that were produced by P doping. It was found that, for donor concentrations which were below about 2 x 1020/cm3, the diffusivity (table 7) depended linearly upon the dopant concentration. However, at higher dopant concentrations, the diffusivity increased markedly with increasing donor concentration. This behavior was successfully modelled in terms of the vacancy-percolation model, and it was concluded that collective phenomena played a significant role at high donor concentrations.
Heavy Doping Effects in the Diffusion of Group IV and V Impurities in Silicon. A.N.Larsen, K.K.Larsen, P.E.Andersen, B.G.Svensson: Journal of Applied Physics, 1993, 73[2], 691-8
Table 7
Diffusivity of As in Si
Temperature (C) | D (cm2/s) |
1100 | 5.0 x 10-12 |
1075 | 3.7 x 10-12 |
1050 | 3.1 x 10-12 |
1025 | 2.1 x 10-12 |
1000 | 1.9 x 10-12 |