Detailed model on amorphous Al-Pt phase growth in thin film systems

Abstract We present an amorphous phase growth model in the Al-Pt thin film system prepared by high-temperature successive deposition (HTSD) under various experimental conditions. Our theory is based on detailed TEM, XTEM and SAED investigations. The model contains a brief explanation of the quasi two-dimensional phase formation on the sample surface during Pt deposition and deals with the diffusional Al transport in the newly developed Al-Pt phases. Theoretical calculations, according to the experimental results, prove the existence of a critical thickness ( L C1 ) of the amorphous phase. Related phenomena of intermetallic phase nucleation (Al 3 Pt 2 ) and amorphous⇒ polycrystalline phase transition are also treated. Additionally, the diffusional limitation of the growth of coexisting amorphous—intermetallic phases could be explained and characterised by the second critical thickness ( L C2 ). It will be shown also that various thin film structures, e.g. thick (250 nm) pure a-Al 2 Pt surface coatings, can be tailored by using HTSD and different parameter ranges.