Atomic scale effects of zirconium and hafnium incorporation at a model silicon/silicate interface by first principles calculations

First principles calculations aimed at quantifying the effects of zirconium and hafnium incorporation at a model silicon/silicate interface have been performed. The tetrahedral bonding character of silicates allows useful comparisons as well as important new distinctions to be drawn with the familiar Si/SiO(2) system. The calculated energy cost of forming (Zr, Hf)-Si bonds suggests that SiO(2)-like bonding is energetically favored over silicide-like bonding at the Si interface. The calculations also suggest that the volume strain associated with Zr or Hf incorporation may lead to increased stress, both in the bulk oxide and in the interfacial transition region.