TY - JOUR T1 - 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. AU - Aït Aïssa,Keltouma, AU - Elmazria,Omar, AU - Boulet,Pascal, AU - Aubert,Thierry, AU - Legrani,Ouadra, AU - Mangin,Denis, PY - 2015/7/14/entrez PY - 2015/7/15/pubmed PY - 2015/7/15/medline SP - 1397 EP - 402 JF - IEEE transactions on ultrasonics, ferroelectrics, and frequency control JO - IEEE Trans Ultrason Ferroelectr Freq Control VL - 62 IS - 7 N2 - 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. SN - 1525-8955 UR - https://www.unboundmedicine.com/medline/citation/26168184/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_ DB - PRIME DP - Unbound Medicine ER -