Comparison of properties between rapid thermally processed and conventional furnace pyrolyzed plzt thin films

Abstract

Abstract PLZT thin films of composition 2/55/45 (La/Zr/Ti) were spin coated from acetate precursors and crystallized by rapid thermal processing (RTP) and conventional furnace pyrolysis (CFP). One experiment isolating the effects of thermal processing from deposition technique involved a comparison of rapid thermally processed films, produced with a computer controlled automatic spin coat reactor/analyzer, with conventional furnace pyrolyzed films, fabricated manually using a photoresist spin technique. Heating rates of at least 70[ddot]C per second for RTP versus 35[ddot]C per second for CFP yielded differences in film properties with thermal processing technique. All of the films were spun on Pt-coated Si substrates and were fired at 700[ddot]C for 15 total minutes; however, different firing schedules were utilized with variable individual layer firing times and post-anneal times. These variable firing schedules also yielded noticeable differences in film properties. Film thickness, measured with a laser ellipsometer, ranged from 0.4 to 0.5 μm. RTP thin films exhibited improved crystallinity, smaller grain size and better saturated hysteresis loops than CFP films. Higher dielectric constants of 715–1700 and lower coercive fields of 34–64 kV/cm were also observed in the RTP films compared to 600–740 and 63–104 kV/cm, respectively, for CFP films.