Evidence for reaction at the Al-SiO2interface

Evidence from X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) is presented for a solid state reaction between aluminium and oxidised silicon, which results in the formation of a crystalline oxide phase of aluminium and elemental silicon. The oxide phase has been identified as a mixture of eta and gamma phases which are less dense and have more 'open' structures than the most stable alpha -Al 2 O 3 phase. The authors suggest that this reaction which can occur under the conditions used for the manufacture of integrated circuits may be significant for electromigration failure mechanisms.