Energy band discontinuities in the a-SiN x/c-Si heterojunction

Abstract

Using the internal photoemission technique and X-ray photoelectron spectroscopy (ESCA) the band discontinuity for the amorphous silicon nitride (a-SiN x ) crystalline silicon (c-Si) heterojunction has been investigated for nitrogen concentrations corresponding to 0 < x < 0.8. The internal photoemission data showed that the conduction band discontinuity (Δ E c) remains constant at about 0.1 eV over the entire range of x investigated. This implies that the 0.85 eV expansion of the band gap over the same range of x is accommodated entirely by the valence band discontinuity (Δ E v). ESCA measurements showed a shift in the valence band edge similar in magnitude to the growth of the a-SiN x band gap thus supporting the conclusion Δ E v is expanding.