Effect of Thermal Oxidation on the Segregation of Phosphorus Implanted into Silicon

Secondary ion mass spectrometry and numerical simulation are used to investigate phosphorus diffusion and segregation in the SiO2-Si(111) system during the thermal oxidation of phosphorus-ion-implanted silicon layers in dry and humid oxygen between 950 and 1150°C. The results demonstrate that the segregation coefficient of phosphorus in SiO2 and Si depends not only on the oxidation temperature and environment but also on the oxidation time, which is interpreted in terms of the variation in the interfacial density of intrinsic point defects as a result of implantation-damage annealing. A model for the reaction segregation of impurities in the SiO2-Si system is used to evaluate the equilibrium segregation coefficient of phosphorus as a function of temperature: = ms* in dry O2 and = 4.2 × 102exp(−0.22 eV/(kT)) in humid O2.