Effective diffusion coefficient and controlling process of P diffusion in Si based on the pair diffusion models of vacancy and interstitial mechanisms

Based on the pair diffusion models of vacancy and interstitial (V and I) me chanisms, the V and I components of effective P diffusion coefficient, D-P,V(eff) and D-P+,I(eff), and the controlling process of P diffusion in Si a re obtained. Assuming that the I mechanism is dominant, not only the I- con centration, CI-, but also its gradient, dC(I-)/d lambda, is effective on D- P+,I(eff) at high CP+. D-P+,I(eff) is large at dC(I-)/d lambda < 0 and smal l at dC(I-)/d lambda > 0. P+ and I- are generated by the dissociation of P- I pair. When excess I- thus generated is removed, dC(I-)/d lambda < 0 is ob tained, dC(I-)/d lambda < 0 is also obtained by the decrease in quasi self- interstitial formation energy. Several diffusion models simulate the P diff usion pmfile well under an inert atmosphere. Applying the controlling proce ss to them, the reason why they simulate the P profile well is investigated . Because all of them simulate the P profile well, it is difficult to concl ude which model is correct. It is suggested that it is possible to conclude which model is correct from the P profile under oxidation at C-P+(s) > 1 x 10(20) cm(-3) (s: surface).