KINETIC-ANALYSIS OF SILICON OXIDATIONS IN THE THIN REGIME BY INCREMENTAL GROWTH

The scaling of dry thermal oxides into the thin (< 400 angstrom) range continues to motivate studies of the rapid initial oxidation rate of silicon unaccounted for by a linear-parabolic model. In this paper, si licon oxidation kinetics in this unresolved regime are studied by the incremental reoxidation of silicon oxidation kinetics in this unresolv ed regime are studied by the incremental reoxidation of thin thermally grown and deposited silicon oxide layers on silicon. It is found that the reoxidation rates of thermally grown oxides in the thin regime ra pidly decrease with increasing oxide thickness. In contrast, the reoxi dation rates of deposited oxides are faster, and nearly thickness inde pendent. It is also found that the reoxidation rates of thin thermal o xides can be significantly increased by inert thermal annealing. Exist ing thin-regime oxidation models are evaluated in light of these exper imental findings, and it is concluded that only models invoking stress suppression of early oxidation kinetics can reconcile all experimenta l observations. In further support of a stress argument, the time and temperature effects of inert annealing are shown to be quantitatively consistent with a Maxwellian model for stress relaxation. Kinetic para meters extracted from experimental data are utilized to isolate specif ic mechanisms for the suppression of oxidation rate during the initial stages of silicon oxidation.