Deposition and characterization of pyroelectric PMN-PT thin films for uncooled infrared focal plane arrays

摘要

Modern uncooled infrared focal plane arrays (UFPA) development is oriented toward silicon microstructure monolithic arrays by employing pyroelectric thin films with continuing trends in high performance and miniaturization. In order to exploit high performance pyroelectric thin films, (1-x)Pb(Mg_(1/3)Nb_(2/3))O_3-xPbTiO_3 (PMN-PT) thin films with x = 0.26 were deposited on LaNiO_3/Si substrates by the radio-frequency magnetron sputtering technique. (110) preferred orientation thin films with pure perovskite structures were obtained at a substrate temperature of 500 ℃. The ferroelectric, dielectric and pyroelectric properties of the films were investigated. The films show a typical polarization - electric filed hysteresis loop with a large remnant polarization of 17.2 uC/cm2. At room temperature, the high pyroelectric coefficient of 3.1 × 10~(-4) C/m~2K together with low dielectric constant of 470 and loss tangent of 0.04 render the film promising for uncooled infrared device applications. The origin of the differences in electrical properties between the films and bulk materials has also been discussed.