Stabilization of cubic CrN0.6 in CrN0.6/TiN superlattices

A transmission electron microscopy study of CrN0.6/TiN superlattices deposited by reactive magnetron sputtering is described. The stable structure of CrN0.60 is hexagonal, but high resolution transmission electron microscopy images of the superlattices showed that CrN0.6 layers less than or equal to 10 nm thick were cubic, while 50 nm thick layers were hexagonal. That is, the cubic CrN structure was "epitaxially stabilized" by the cubic TiN, with which there is a 2.4% lattice mismatch. The superlattices with hexagonal CrN0.6 showed high strains and defect densities within approximate to 5 nm of each interface, presumably due to the 5.4% volume decrease associated with the cubic-to-hexagonal transformation. The effect of this strain on the transformation is discussed. (C) 1998 American Institute of Physics.