Crossover of texture and morphology in (Ti1 − xAlx)1 − yYyN alloy films and the pathway of structure evolution

In our earlier published work, we have shown that there is a composition range of the (Ti1 − xAlx)1 − yYyN alloy films (0.72 < Ti/Al < 0.88) deposited at oblique vapour beam incidence and 500 °C (corresponding to zone T) in which mixed cubic TiN (c-TiN) and wurtzite AlN (w-AlN) structures were formed together with an unusual complex texture. The texture of c-TiN phase changed from 〈001〉 to <111> at a certain thickness forming a definite crossover. Moreover the c-TiN<111> and the w-AlN〈0001〉 crystals were epitaxially related with axes tilted to the direction of the vapour beam. on a comprehensive transmission electron microscopy (TEM) and diffraction (XRD and selected area electron diffraction (SAED)) structure and morphology analysis, we discovered the details of this exotic structure making it possible to construct the complex pathway of structure evolution including the formation of the w-AlN phase and the change of the dominating texture of c-TiN phase with thickness in dependence of the Ti/Al ratio and the deposition parameters. This pathway could be deduced from the fundamental phenomena of structure formation and may be generalised for multi-component thin film systems. A composition structure zone model has been also proposed for the (Ti1 − xAlx)1 − yYyN thin film system in the 0 < x < 1 composition range.