Growth of SiCAlN on Si(111) via a crystalline oxide interface

Growth of single-phase SiCAlN epitaxial films with the 2H-wurtzite structure is conducted directly on Si(111) despite the structural differences and large lattice mismatch (19%) between the two materials. Commensurate heteroepitaxy is facilitated by the conversion of native and thermally grown SiO₂ layers on Si(111) into crystalline oxides by in situ reactions of the layers with Al atoms and the H₃SiCN precursor, forming coherent interfaces with the Si substrate and the film. High-resolution transmission electron microscopy and electron energy-loss spectroscopy show that the amorphous SiO₂ films are entirely transformed into a crystalline Si-Al-O-N framework in registry with the Si(111) surface. This crystalline interface acts as a template for nucleation and growth of epitaxial SiCAlN. Integration of wide-band-gap semiconductors with Si is readily achieved by this process.