Experimental determination of band offset energies between Zr silicate alloy dielectrics and crystalline Si substrates by XAS, XPS and AES and ab initio theory: a new approach to the compositional dependence of direct tunneling currents

XPS, AES and XAS studies of non-crystalline Zr silicate alloys have identified the band edge electronic structure, and the compositional dependence of valence and conduction band offset energies. These results are integrated into a two band tunneling model for a conduction band with localized Zr 4d* followed by extended Si 3s* states with composition-independent conduction band offset energies, respectively, of /spl sim/1.4 and 3.2 eV. The model predicts a minimum tunneling current for ZrO/sub 2/ content in the mid-alloy composition range.