Segregation

Segregation is a coefficient defined as the ratio of impurity concentrations at both sides of two different layers, which influences the diffusion profiles. However, the ratio is rarely in thermal equilibrium in general cases. Hence, the evaluation of the value of the segregation is difficult. It is found that the thermal equilibrium of segregation has been established in the redistribution profile of impurities in oxidized polycrystalline Si (polysilicon) because the diffusion coefficient is much larger than that in Si. The redistribution model is derived, and related segregation values are evaluated.

Keywords: Segregation, thermal equilibrium, polycrystalline silicon, diffusion, redistribution, chemical potential, interface, Si/SiO2 interface, oxidation, transport coefficient, chemical vapor deposition, B, As, SIMS, SiO2/polysilicon interface, absorption coefficient, dose.