Theory of thePbcenter at the Si/SiO2interface

Abstract

We present a series of semiempirical calculations on threefold-coordinated silicon at the 〈111〉 Si/${\mathrm{SiO}}_2$ interface. These were performed on finite clusters of atoms with use of hydrogen terminators in an unrestricted Hartree-Fock formalism wherein we include lattice relaxations. We have calculated defect electrical levels as well as ESR hyperfine parameters. The agreement with Brower’s principal hyperfine data is excellent. On the strength of this agreement, we assign the superhyperfine shoulders to spin density on three second-nearest-neighbor silicon atoms in the crystalline silicon. Our agreement with electrical data is good; we obtain a positive U of between 0.3 and 0.6 eV, depending upon the method of calculation. Finally, we predict the existence of a spin-dependent deep-level transient-spectroscopy signal at high pressure.