Achieving Up To 10 µm epitaxial AlN films on none heated composite substrates using DC magnetron sputtering
Abstract
Thermal management materials are considered as the cornerstone of both high temperature lasers and electronic devices. In the present work, aluminum nitride (AlN) films are a vital component owing to their high thermal conductivity for such specific applications. A comprehensive study was performed on the epitaxial growth of AlN films in order to control stress and address thickness limitations issues. In this frame, AlN films were grown on none heated composite substrates(sapphire) using DC reactive magnetron sputtering (DCMS). AlN microstructure, films interface and residual stress were tracked. Using high N2-flow during AlN film growth was a key factor as it significantly enhances the crystalline quality and the maximum achievable thickness of the sputtered films. Narrow FWHM-RC values of about 0.2° were obtained for thicknesses ranging from 0.5 to 10 µm. Moreover, thanks to the use of ultra-fast transient hot-strip technique, a thermal conductivity of kb = 200 ± 60 Wm–1K–1 and an interface thermal resistance of R = (2.0 ± 0.5) x 10–9 m2KW–1 were estimated. In order to better understand such a significant increase in maximum achievable film thickness, the residual stress developed within the film was investigated. A high compressive residual stress is observed for thin AlN films and stress relaxation occurs when the thickness increases. A transition from compressive to tensile stress is likely to be observed with increasing film thickness. However, the stress remained compressive throughout film growth, which prevented delamination up to 10 µm. This result is crucial especially for specific applications that require thick epitaxial AlN films.
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BibTeX
@article{zernadji2026achieving,
title = {{Achieving Up To 10 µm epitaxial AlN films on none heated composite substrates using DC magnetron sputtering}},
author = {R. Zernadji and B. Riah and S. Meddour and R. Beldjedra and B. Garnier and A. Ayad and B.E. Belkerk and M.A. Djouadi},
journal = {Surfaces and Interfaces},
year = {2026},
month = aug,
doi = {10.1016/j.surfin.2026.109737},
url = {https://hal.science/hal-05685164v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Achieving Up To 10 µm epitaxial AlN films on none heated composite substrates using DC magnetron sputtering
AU - R. Zernadji
AU - B. Riah
AU - S. Meddour
AU - R. Beldjedra
AU - B. Garnier
AU - A. Ayad
AU - B.E. Belkerk
AU - M.A. Djouadi
PY - 2026
DA - 2026/08/15
JO - Surfaces and Interfaces
DO - 10.1016/j.surfin.2026.109737
UR - https://hal.science/hal-05685164v1
AB - Thermal management materials are considered as the cornerstone of both high temperature lasers and electronic devices. In the present work, aluminum nitride (AlN) films are a vital component owing to their high thermal conductivity for such specific applications. A comprehensive study was performed on the epitaxial growth of AlN films in order to control stress and address thickness limitations issues. In this frame, AlN films were grown on none heated composite substrates(sapphire) using DC reactive magnetron sputtering (DCMS). AlN microstructure, films interface and residual stress were tracked. Using high N2-flow during AlN film growth was a key factor as it significantly enhances the crystalline quality and the maximum achievable thickness of the sputtered films. Narrow FWHM-RC values of about 0.2° were obtained for thicknesses ranging from 0.5 to 10 µm. Moreover, thanks to the use of ultra-fast transient hot-strip technique, a thermal conductivity of kb = 200 ± 60 Wm–1K–1 and an interface thermal resistance of R = (2.0 ± 0.5) x 10–9 m2KW–1 were estimated. In order to better understand such a significant increase in maximum achievable film thickness, the residual stress developed within the film was investigated. A high compressive residual stress is observed for thin AlN films and stress relaxation occurs when the thickness increases. A transition from compressive to tensile stress is likely to be observed with increasing film thickness. However, the stress remained compressive throughout film growth, which prevented delamination up to 10 µm. This result is crucial especially for specific applications that require thick epitaxial AlN films.
SN - 2468-0230
ER -