Lead lanthanum titanate($Pb_{1-x}La_xTiO_3$, PLT) thin films were fabricated using sol-gel method onto Pt/Ti/$SiO_2$/Si substrates, dried at different temperatures from 400℃ to 440℃ and then, fired at different temperatures from 550℃ to 650℃ using rapid thermal annealing(RTA). The X-ray diffraction(XRD) pattern, microstructure, dielectric properties, polarization vs. electric field(P-E) curve, pyroelectric coefficient, voltage responsivity, etc. were investigated. Effects of the drying temperature and the firing temperature on the properties of PLT thin films are negligible. PLT thin films with high La concentration have the preferred (100) orientation and small grains due to the higher nucleation sites. The fracture surfaces of the films with high La concentration show columnar structure of which the grains grew from the bottom electrode. Dielectric constant, dielectric loss and pyroelectric coefficient increased and remanent polarization, coercive field decreased with the La concentration, which may be due to the concentration of vacancy in the films. To improve the voltage responsivity, the back side of the substrate was etched. The etching solution was 30 wt.% KOH and etching temperature was 90∼95℃. The voltage responsivity was improved when the back side of the substrate was etched, which may be due to the decrease of the thermal mass and thermal conductance.
