Nanoscale Transition Metal Thin Films: Growth Characteristics and Scaling Law for Interlayer Formation

A comprehensive study on the growth of nanoscale transition metal – on – transition metal (TM-on-TM) systems is presented. The near room temperature intermixing and segregation phenomena during growth are studied in vacuo using high-sensitivity low energy ion scattering (HS-LEIS). The investigated TM-on-TM systems are classified into four types according to the observed intermixing and segregation behavior. Empirical rules are suggested to qualitatively predict the growth characteristics of any TM-on-TM system based on the atomic size difference, surface energy difference and enthalpy of mixing between the film and substrate atoms. An exponential trend is observed in the effective interface width as a function of the surface energy difference between the film and substrate layers, with a subtrend based on the crystal structure of the TM layers. A semi-empirical model that accurately describes the experimental data is presented. It serves as a scaling law to predict the effective interface width and the mi...