Four diffusion models, based upon the pair-diffusion vacancy and interstitial mechanisms, were applied to the simulation of 6 experimental profiles of P surface concentration, CP+s, from 3 x 1020 to 2.5 x 1018/cm3 at 900C. Values of fitting parameters were determined in order to simulate the profiles of CP+s = 3 x 1020 and 2.5 x 1018/cm3 closely. By changing only CP+s, other profiles were simulated. At high CP+s, a large amount of excess I was generated. In order to simulate CP+s = 3 x 1020/cm3, it was necessary to control excess I. To simulate CP+s below 3 x 1020/cm3, the effect of a principal parameter upon the control of excess I had to decrease with decreasing CP+s. The decrease in the quasi self-interstitial formation energy, or the ratio of the diffusion coefficient of a negatively charged P-V pair to that of a neutral one, was deemed to be suitable as such a parameter. In order to deduce a suitable principal parameter, it was necessary to obtain more accurate experimental profiles, and to pay attention as to whether or not the profile exhibited a plateau.

Simulation of Phosphorus Diffusion Profiles with Different Phosphorus Surface Concentration at the Same Diffusion Temperature in Silicon. M.Yoshida, S.Tanaka: Japanese Journal of Applied Physics - 1, 2002, 41[9], 5493-502

Table 15

Diffusivity Ratios of 30Si and P in Si during Oxidation at 800 to 1100C