We have calculated the effect of the oxidation-induced strain on the ballistic conductance in a Si/ SiO 2 quantum point contact. The strain-induced deformation potential was calculated semiempirically using a viscoelastic continuum model. The charge carriers are confined to the corners of the waveguide by both the strain-induced deformation potential and the Si/ SiO 2 band edge discontinuity. As a consequence nearly degenerate symmetric and antisymmetric transverse states are formed for the Si

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... 001͔ minima. This additional degeneracy within the Landauer-Büttiker formalism leads to doubling of conductance steps for electrons in the ͓001͔ minima which govern the conductance near the cutoff energy. Due to the additional strain-induced confinement, the effective channel width of the quantum point contact is smaller and therefore the conductance steps are sharper.