(The) effect of $Si-SiO_2$ interface on the excess point defect distribution in silicon

Abstract

The influence of unoxidizing Si-$SiO_2$ interface on the distribution of excess point defects in silicon, excess interstitials during thermal oxidation and excess vacancies during high concentration phosphorus diffusion, was investigated experimentally and numerically. A new phenomenological parameter called excess point defect recombination velocity (S) at the unoxidizing Si-$SiO_2$ interface was proposed. By comparing calculated normalized excess point defect concentration profiles with the experimental data of normalized diffusivity increments of impurity atoms, the values of S/$D_{pd}$ ($D_{pd}$ is the diffusivity of point defects in silicon) were found out to be 2.8 - $16.\times10^3$/cm for excess interstitials and 2.5 - $10\times10^3$/cm for excess vacancies. Expanding Hu``s model of excess interstitial trapping at the Si-$SiO_2$ interface to both interstitials and vacancies, the surface density of the excess point defect recombination centers at the unoxidizing Si-$SiO_2$ interface were also found out to be 1.6 - $9.4\times10^{10}/cm^2$ for excess interstitials and 2.5 -$5.8\times10^{10}/cm^2$ for excess vacancies.