Boron impurities on a vicinal Si(100) surface: a study of structural properties and binding energies

The equilibrium locations of boron on the steps of the Si(100) surface have been studied using the Hartree-Fock method at the semiempirical level. The step is represented by a cluster of silicon atoms whose dangling bonds are saturated by hydrogen atoms. The boron impurity is moved in the step in substitutional and interstitial positions and the optimal configuration of the step containing the impurity is evaluated from a steepest-descent energy minimization. The study focuses on the dependence of the properties of the boron-step interaction on the shape of the step. These effects are analysed in the light of the features of boron absorbed on the flat surfaces and in the bulk, which have been widely studied.