Effect of temperature on the growth of TiN thin films by oblique angle sputter-deposition: A three-dimensional atomistic computational study
Résumé
Kinetic Monte Carlo (kMC) atomistic computations using MODENA code were employed to simulate the growth of columnar TiN thin films under oblique angle deposition geometry. The influence of substrate temperature (300, 400 and 500 K) on the morphology (column tilt angle, average layer density, compactness, surface roughness) of the layers was studied by varying the inclination angle α of the substrate from 5° to 85° with respect to the centerline of the source. Two types of simulations were considered in this work: the first one assumes a collimated flux (CF) of incident particles and the second one grasps the angular distribution of sputtered Ti particles to closely mimic the magnetron sputtering (MS) conditions. The formation of separated columns with high aspect ratio, and tilted in the direction of the incident particles flux, is observed for α ≥ 35° for the two types of particle flux. The column width and tilt angle, the average layer density and the compactness of the TiN films are found to increase with increasing substrate temperature, due to enhanced surface diffusion. The column tilt angle β increases from 3° to 60° with increasing α for the CF case, while it saturates to approx. 35° when the MS distribution is considered. The relationship between β and α, and their temperature dependence, are discussed and compared to experimental results obtained on sputter-deposited TiN films, as well as with other results and models reported in the literature. The code also reproduces morphological features common to most films produced at glancing angles, such as column broadening with increasing thickness and their anisotropic aggregation (bundling association) in the transverse direction.
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