Jasminka Terzic

Zirconium (Zr) thin films were deposited on silicon (Si) substrates via pulsed laser deposition (PLD) using a 248 nm excimer laser. The effects of substrate temperature on film morphology and crystallinity were systematically investigated. X-ray diffraction (XRD) revealed that the Zr(100) plane exhibited the strongest orientation at 400 °C while Zr (002) was maximum at 500 °C. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses demonstrated an increase in surface roughness with temperature, with the smoothest surface observed at lower temperatures and significant island formation at 500 °C due to the transition to 3D growth. At 500 °C, interdiffusion effects led to the formation of zirconium silicide at the Zr/Si interface. To further interpret the experimental findings, computational modeling was employed to analyze the transition from 2D layer-by-layer growth to 3D island formation at elevated temperatures. Using a multi-parameter kinetics-free model based on free energy minimization, the critical film thickness for this transition was determined to be ~1–2 nm, aligning well with experimental observations. A separate kinetic model of island nucleation and growth predicts that this shift is driven by the kinetics of adatom surface diffusion. Additionally, the kinetic simulations revealed that, at 400 °C, adatom diffusivity optimally balances crystallization and surface energy minimization, yielding the highest film quality. At 500 °C, the rapid increase in diffusivity leads to the proliferation of 3D islands, consistent with the roughness trends observed in SEM and AFM data. These findings underscore the critical role of deposition parameters in tailoring Zr thin films for applications in advanced coatings and electronic devices.

Zirconium (Zr) thin films were deposited on silicon using pulsed laser deposition (PLD) with two laser wavelengths (1064 nm and 532 nm) and varying substrate temperatures (25 °C, 300 °C, and 500 °C) and laser fluences (0.25, 0.5, 1.0 J/cm²). Results indicate that smoother films were obtained with 1064 nm and surface roughness increased with higher fluences. Optimal crystalline films were obtained at 300 °C. XRD, SEM, and AFM analysis revealed distinct patterns and peaks related to laser parameters. The growth mechanisms of a Zr film were computed based on a well-known continuum model of thin film growth. Our simulations agree with experimental observations. The study highlights crucial factors affecting Zr thin film deposition and provides insights for optimizing PLD parameters to achieve high-quality films.