Abstract
This thesis relates differents steps for manufacturing IR pyroelectric detector with LiTaO3 thin films. The first chapter treats pyroelectric effect in IR detectors. LiTaO3 cristal's chemical and physical properties are shown in second chapter. The characterisation tools and technicals of deposition used to realise the study system (top electrode / pyroelectric film / back electrode) are presented in the third chapter. The fourth and the fifh chapters respectively present the material study of ruthenium oxide thin films deposited by RF sputtering which are used as back contact and the material study of the pyroelectric LiTaO3 thin films elaborated by RF magnetron sputtering. The top electrode is deposited by thermal evaporation of Al or by RF sputtering for NiCr contacts. In the sixth chapter, dielectric characterisations showed that Ru film presence at interface between RuO2 film and substrate decreases the dielectrics loses. These characterisations also showed the influence of LiTaO3 growth conditions on their dielectric properties. These results are in agreement with measurements of pyroelectric coefficients presented in the seventh chapter. In addition, this chapter examines the effect of parasite charges on the pyroelectric current. In part, the effect is attributed to interface between LiTaO3 and back electrode. For Li enriched target, the thin films can present pyroelectric coefficient equal to 55 µC/cm2K ( LiTaO3 bulk crystal is 180 µC/cm2K). The last chapter is devoted to IR pyroelectric detector realisation (micro usining, associated electronic) and current reponsivity