Planar oxidation of strained silicon substrates

We report here on a series of experiments in which relatively low levels of in-plane bending strain were applied to oxidizing silicon substrates. These were found to result in significant decreases in oxide thickness in the ultrathin oxide regime. Both tensile and compressive bending resulted in roughly the same degree of thickness retardation, although compressive bending typically led to somewhat thinner oxides than did tensile bending. An examination of the experimental data indicate that the principal effect seems to occur in the very early stages of oxidation, with only minor effects on subsequent oxide growth. We hypothesize that the observed oxide thickness retardation is related to straining of the underlying silicon lattice at the oxidation front.