Thermal Laser Epitaxy for Nitride Growth: A Case Study in Aluminum Nitride

Thermal laser epitaxy (TLE) is an emerging technique that broadens the scope of growth parameters for thin film deposition. In this study, we investigate the potential of TLE for growing nitride films, focusing specifically on aluminum nitride (AlN). The TLE process employs laser evaporation of high-purity aluminum in a nitriding atmosphere using either plasma-generated nitrogen radicals or NH3 gas. We examine AlN growth behavior across substrate temperatures up to desorption-limited conditions and a wide range of V/III ratios from Al-rich to N-rich environments. A self-consistent kinetic flux model is introduced to interpret the competition among nitrogen activation, Al incorporation, and thermally activated desorption, enabling identification of N-limited, supply-limited, and desorption-limited growth regimes. Using NH3 enables growth rates of approximately 0.9 μm/h, with further enhancement possible through optimized flux balance. Moreover, high-temperature annealing within the TLE chamber improves crystallinity and surface morphology of AlN films. The versatility of TLE, spanning molecular-flow to viscous-flow regimes combined with high-temperature processing, makes it a promising platform for controllable nitride growth.