Investigation of pyroelectric characteristics of lead titanate thin films for microsensor applications

Abstract

Pyroelectric PbTiO3 thin films deposited on Si(100) substrates (Pt/Ti/SiO2/Si) by sol-gel processing have been characterized in some detail to determine the usefulness of these films for uncooled detector applications. The films have been deposited without substrate heating. The amorphous films were than annealed in air for a half hour at 400–700 °C. X-ray diffraction patterns taken on these films showed single-phase tetragonal perovskite structure with a slight c-axis preference. The grain size was in the range of 0.2–0.3 μm. The D–E hysteresis loop characteristics were performed, as well as measurements of the dielectric and pyroelectric properties versus temperature and frequency. The influence of dc bias treatment on the dielectric and pyroelectric properties was investigated. The results of measurements show that PbTiO3 thin films exhibit a relatively high pyroelectric coefficient relative to the dielectric permittivity, contributing to a very high figure of merit for voltage responsivity that is competitive with PbTiO3 single crystal and PZT thin films.