Study Of The Preparation And Properties Of New Type PST Ferroelectric Thin Films

PbSc0.5Ta0.5O3 (PST) has higher pyroelectric efficient, higher dielectric constant, lower dielectric loss and higher detecting merits than other common pyroelectric materials, PST has the advantages of ambient temperature operation, low power consumption, low in-service costs, low weight and compactness. PST has been widely used in uncooled infrared focal plane arrays (UFPA) and has involved more interesting. This paper aimed at systematically studying the Sol-Gel techniques and properties of the progress of PST thin films. This is the foundation of research and development for device of PST thin films. The PST ferroelectric thin films are synthesized on Pt/Ti/SiO2/Si substrates by improvel Sol-Gel technique. The starting materials were tantalum ethoxide (Ta(OC2H5)5), scandium acetate (Sc(CH3COO)3·xH2O ),lead acetate (Pb(CH3COO)2·3H2O) ,monoethanolamine and dissolved in 2-methoxethanol (CH3OCH2CH2OH). The reaction mechanism of PST gels has been studied. The influences of annealing time and annealing temperature on the crystallinity formation, properties of the films have also been investigated. PST thin films with crack-free and compact have been successful fabricated.PST thin films that have been prepared were analyzed by X-ray diffraction (XRD) and scanning electron micrograph (SEM). The experimental results show that PST thin films that have been prepared were crack-free and compact with few impurity phases. The results show that the optimum processing for PST films is RTA 750℃×15min or RTA 800℃×5min and PT seed layers.Dielectric,ferroelectric and pyroelectric properties of PST thin films have been tested. The pyroelectric coefficient of PST thin films are 7.4×10-4Cm-2K-1 and detecting merits is 2.7×10-5Pa1/2.