Role of point defects in the growth of the oxidation-induced stacking faults in silicon. II. Retrogrowth, effect of HCl oxidation and orientation

A new mechanism, describing the growth of the oxidation-induced stacking faults (OISF) in silicon was described earlier. The length of the fault was given by the equation L=k^'p_O₂ᵐtⁿexp(-Q/kT). In this paper, two new concepts are introduced which, without changing the basic formulation of the above mechanism, account for the observed temperature dependence of m and n and for the effect of chlorinecontaining oxidizing ambients on the fault growth. (a) It is postulated that, in addition to the pO2 dependence, the concentration of the interstitial silicon [SiI], generated in silicon at the SiO₂-Si interface, decreases with the increasing rate at which the SiO₂-Si interface moves in the silicon. It is then assumed that [SiI]∝(oxidationrate)^-q. q is a number which is found to be related to the difference between the parabolic oxidation-rate constant and the self-diffusion coefficient of silicon. Incorporation of this concept leads to the equation of the length of the OISF which is similar to above equation but which predicts temperature-dependent m and n. In addition, a retrogrowth phenomenon is postulated to occur when q changes from being positive to negative. Negative q values lead to very small values for k^'. (b) In the presence of chlorine-containing species, the interstitial silicon concentration decreases either due to direct consumption of the interstitial or due to generation of vacancies at the SiO₂-Si interface. In either case, a SiCl complex is formed, leading to a reduced OISF growth rate (or shrinkage of existing faults) or to a nogrowth condition. A comparison with the available data leads to the conclusion that, for the reduced-growth conditions in HCl-O₂ ambients, L∝pHCl^-3/8, and that one silicon atom complexes with two chlorine atoms. Finally, the orientation dependence of the OISF growth is also discussed.