Recent progress in sputtering PZT thin films for ferroelectric memories |
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Authors: | Tomoyuki Sakoda Katsuhiro Aoki Satoshi Hashimoto Yukio Fukuda |
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Affiliation: | 1. Texas Instruments Tsukuba Research &2. Development Center Ltd. , 17 Miyukigaoka, Tsukuba , Ibaraki , 305-0841 , Japan |
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Abstract: | Abstract This paper describes amorphous Pb(Zr, Ti)O3 (PZT) thin films deposited by cosputtering Pb(Zr0.5 Ti0.5)O3 and PbO targets. By optimizing the amount of the excess Pb and the deposition temperature, PZT thin films with a single perovskite phase were obtained successfully on Ir substrates and Pt substrates at 520°C. 250-nm-thick PZT films crystallized by rapid thermal annealing (RTA) at 600°C for 20 s exhibited excellent ferroelectric properties: a coercive voltage of 1.0 V, a remanent polarization density of about 40 μC/cm2, and a polarization switching endurance over 1x109 cycles. Although a heat treatment in a reductive ambient causes degradation of ferroelectric properties of PZT thin films, their degraded ferroelectric properties can be easily recovered from by a 1-min RTA in an oxygen at 400°C. |
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Keywords: | amorphous PZT sputtering excess Pb hydrogen-damaged capacitor rapid thermal process ferroelectric memory |
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