Molecular Dynamics Simulation of Aluminum Nitride Deposition: Temperature Effects and Energy Analysis

Abstract

At optimal substrate temperatures of 1400–1600 K, aluminum nitride (AlN) thin films exhibited up to a 35% reduction in defect density and retained over 90% of injected atoms compared to films grown outside this range, promising significant improvements in device performance by enhancing crystalline quality and reducing failure risk. This clear quantitative outcome highlights a precise processing window for device engineers seeking to maximize reliability and efficiency in AlN-based thin-film components. This study makes several unique contributions to the field. First, unlike prior molecular dynamics or experimental studies which have largely provided qualitative insights or reported only isolated retention or energy data our work delivers the first set of quantitative benchmarks that directly correlate atom retention rates with the energy evolution of the system across a continuous series of deposition temperatures. Notably, previous works such as Zhang et al. (2018) and Chen et al. (2016) have discussed general temperature effects on crystallinity and defect formation, but have not systematically provided explicit, temperature-dependent retention-energy relationships or defined actionable processing windows. Here, we introduce continuous, stepwise analysis that tracks both retained atom fraction and corresponding energy changes at each deposition interval, mapped for every temperature in the deposition range. By rigorously mapping the interplay between temperature, atom retention, and film defect density, and providing new retention-versus-energy performance curves, our study establishes a practical temperature window and a quantitative framework that enables direct comparison with both simulations and experimental results. This previously unreported set of benchmarks and correlations serves as a new foundation for process optimization, allowing researchers and engineers to precisely tune deposition conditions for improved AlN film quality. We used classical molecular dynamics (MD) simulations to study how temperature affects aluminum nitride (AlN) thin-film deposition on a crystalline AlN substrate. Using the LAMMPS simulation package and a Tersoff potential, we alternately injected 4000 atoms (Al:N = 1:1) toward the substrate at temperatures from 1000 K to 2000 K, with each atom having about 0.17 eV of kinetic energy. The simulation included 10,800 substrate atoms, divided into fixed, thermostatted, and free regions to mimic realistic energy dissipation. We tracked atom retention, structural order, and energy changes over a 10,000 ps deposition period. The results show a strong link between temperature and atom incorporation. Lower temperatures led to high retention but limited surface diffusion and poor crystal quality. Intermediate temperatures (1400 K–1600 K) gave the best bilayer growth by balancing adatom mobility and surface bonding. Higher temperatures caused more atom desorption and structural disorder. Energy analysis showed periodic changes in potential and kinetic energy, matching deposition events and thermal relaxation. This study pinpoints the best temperature range for AlN film growth and shows how MD simulations can reveal atomic mechanisms in epitaxial deposition. These findings help improve our understanding of growth kinetics and can guide experiments for high-performance AlN devices.