Shear-mode thin film bulk acoustic resonator (TFBAR) devices with c-axis tilted AlN films are fabricated for the application of liquid sensors. To fabricate shear-mode TFBAR devices, the off-axis RF magnetron sputtering method for the growth of piezoelectric AlN thin films is adopted and influences of the relative distance and the sputtering parameters are investigated. The shrar-mode phenomenon of a TFBAR results from the tilted crystalline orientation of AlN thin films. In this thesis, the AlN thin films are deposited with tilting angles of 15¢X and 23¢X, set by controlling the deposition parameters. The properties of the AlN thin films are investigated by X-ray diffraction and scanning electron microscopy. The frequency response is measured using an HP8720 network analyzer and a CASCADE probe station. The frequency response of the TFBAR device with 23¢X tilted AlN thin film is measured to reveal its ability to provide shear-mode resonance. The resonance frequencies of the longitudinal and shear modes are 2.07 GHz and 1.17 GHz, respectively. To investigate the sensing characteristics of TFBAR, two basic experiments of mass and liquid loading are carried out. The sensitivities of the longitudinal and shear modes to mass loading are calculated to be 2295 Hz cm2/ng and 1363 Hz cm2/ng with the mechanical quality factors of 588 and 337, respectively. However, the mechanical quality factors of the longitudinal mode of TFBAR without and with a liquid loading decreased from 588 to 0, whereas those remain almost the same for the shear mode under liquid loading. The sensitivities of the longitudinal and shear modes are calculated to be 0 and 17.88 Hz cm2/£gg for liquid loading.

Ce projet est consacré à l'étude des propriétés optiques des films minces en nitrure d'aluminium dopé par des terres rares. Plus particulièrement, le travail est orienté pour étudier les mécanismes de luminescence des éléments RE sélectionnés incorporés dans des films minces AlN pour être utilisés comme candidats aux dispositifs d'éclairage. Au cours de cette thèse, la technique de pulvérisation de magnétron réactif est utilisée pour synthétiser les films minces AlN non dopés et dopés. La technique et le traitement des films sont discutés en détail. L'effet des conditions de pulvérisation sur la structure et les propriétés optiques des films préparés est étudié. La corrélation entre les conditions de pulvérisation cathodique, l'orientation cristallographique, la morphologie, la microstructure et les propriétés optiques sont établies. Les analyses de structure et de composition des échantillons préparés ont été étudiées par plusieurs moyens, tels que la microscopie électronique à transmission, la spectroscopie à rayons X à énergie dispersive et la spectrométrie de rétrodiffusion Rutherford. Les propriétés optiques des films sont caractérisées par une transmission UV-Visible, une spectroscopie d'Ellipsometry et une spectroscopie de photoluminescence / This project is dedicated to study the optical properties of rare earth-doped aluminum nitride thin films. More particularly, the work is oriented to investigate the luminescence mechanisms of selected RE elements incorporated in AlN thin films to be used as a candidate for lighting devices. During this thesis, reactive magnetron sputtering (RMS) technique is used to synthesize the undoped and doped AlN thin films. The technique and films processing are discussed in details. The effect of sputtering conditions on the structure and optical properties of the prepared films are investigated. The correlation between the sputtering conditions, the crystallographic orientation, the morphology, the microstructure and the optical properties are established. The structure and composition analyses of the prepared samples have been investigated by several means, such as transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), and Rutherford backscattering spectrometry (RBS). The optical properties of the films are characterized by UV-Visible transmission, Ellipsometry spectroscopy, and Photoluminescence spectroscopy