In this thesis, the lithium tantalite [LiTaO3, abbreviated to LT] thin films were deposited on Pt/Ti/SiO2/Si substrates by spin coating with sol-gel processing and rapid thermal processing. 1,3 propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of thin film. By changing the heating rate (600~3000¢J/min) and the heating temperature (500~800¢J), the effects of various processing parameters on the thin films growth are studied. In addition, the thermal isolation of detecting elements was achieved by the anisotropic wet etching of back silicon substrate. In order to reduce the thermal mass and thermal time constant of detector, the sensing element was built-up on a thin membrane. By changing the membrane thickness (20~350 £gm), the effects of various membrane thickness on the response of pyroelectric IR detector devices are studied also. Experimental results reveal that the heating rate will influence strongly on grain size, dielectricity, ferroelectricity and pyroelectricity of LT thin films. With the increase of heating rate, the grain size of LT thin film decreases slightly, and the c-axis orientation is enhanced. The relative dielectric constant (£`r ) of LT thin film increases from 28 up to 45.6, the dielectric loss (tan