Preparation and characterization of lead zirconate titanate thin films grown by RF magnetron sputtering for pyroelectric infrared detector arrays

Abstract

One of the challenges in fabricating pyroelectric infrared (PIR) detector arrays using microelectromechanical system (MEMS) technique lies in finding an optimal growth method of sensing thin films. In this study, lead zirconate titanate (PbZr0.3Ti0.7O3, PZT) thin films were successfully prepared on Pt/TiO2/Si3N4/SiO2/Si substrates by RF magnetron sputtering. The structure, morphology and electrical properties of the films annealed at different temperatures were investigated. PZT thin films deposited at a working pressure of 3.0 Pa with an Ar/O2 gas flow ratio of 80/20 and annealed at 700 °C exhibited smooth surface and excellent dielectric, ferroelectric and pyroelectric properties. The dielectric constant and the loss tangent of the films are 500 and 0.018 at 1 kHz, respectively. The remnant polarization (Pr) and the coercive field (Ec) of the films are 33 μC cm−2 and 42 kV cm−1, respectively. The pyroelectric coefficient of the films is 0.033 μC cm−2 K−1. The value of the figure of merit of detectivity (FD) of PZT thin films reaches up to 1.29 × 10−5 Pa−1/2, which indicates that the films have met the requirements for sensitive layers utilized in pyroelectric infrared detector arrays.