Electronic structure and Schottky-barrier heights of (111)NiSi2/Si A- and B-type interfaces

Abstract

The electronic structures of ${\mathrm{NiSi}}_2$/Si(111) A- and B-type interfaces are calculated within the local density approximation (LDA) using large supercells and the LMTO full-potential and ASA methods. The Schottky-barrier heights for the two interfaces differ by 0.14 eV, in agreement with experiment. The difference is caused by a partly filled interface band present in both structures. The LDA barrier heights $E_F$-$E_v$ are both 0.4 eV too low, and insensitive to interface relaxations and to external potentials. The correct density-functional expression for the barrier height is $E_F$-$E_v$+Δ$v_{\mathrm{xc}}$, where Δ$v_{\mathrm{xc}}$ is a nonlocal correction.