Deep state defects in strained and relaxed epitaxial Si1−xGex on Si introduced by 3d transition metal and 5d noble metal impurities

Abstract

This study describes deep state defects introduced in the epitaxial Si1−xGex on Si substrates by 3d transition metal (Fe, Ti, Cr, Ni) and 5d noble metal (Au, Pt) impurities. The deep state activation energy is related to the Ge concentration and strain in the Si1−xGex. The strain dependence is described in terms of the deep state uniaxial and hydrostatic deformation potentials. The difference between the deep state activation energies in Si and Si1−xGex does not agree with the independently determined Si–Si1−xGex band offsets. This demonstrates that the concept of 3d state as an independent, internal reference level, well established for III–V and II–VI compounds, fails in the case of group IV semiconductors.