@Article{Supelec932,
author = {Keltouma Aït Aïssa and Omar Elmazria and Pascal Boulet and Thierry Aubert and Ouarda Legrani and Denis Mangin},
title = {{Investigations of AlN thin film crystalline properties in a wide temperature range by in situ X-Ray diffraction measurements: correlation with AlN/Sapphire based SAW structure performance}},
journal = {IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Institute of Electrical and Electronics Engineers},
year = {2015},
volume = {62},
number = {7},
pages = {1397-1402},
month = {jul},
doi = {10.1109/TUFFC.2014.006868},
abstract = {Aluminum nitride on sapphire is a promising substrate for SAW
sensors operating at high temperatures and high frequencies.
To get a measure of the suitability and temperature stability
of such devices, an experimental relationship between the SAW
performance and the structural properties of the AlN thin
films was investigated in the temperature range between the
ambient temperature and 1000°C. The crystalline structure of
the AlN films was examined in situ versus temperature by X-ray
diffraction. The results reveal that the AlN films remain
(002) oriented even at high temperatures. A gradual increase
of the tensile stress in the film due to the thermal expansion
mismatch with the substrate has been observed. This increase
accelerates around 600°C as the AlN film crystalline quality
improves. This phenomenon could explain the amelioration in
the SAW performance of AlN/sapphire devices observed
previously between 600°C and 850°C. At higher temperatures,
surface oxidation of the AlN films reduces the SAW
performance. The potential of ZnO thin films as protective
layers was finally examined.}
}