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Deposition and Characterization of Ferroelectric Pb[(Mg 1/3 Nb 2/3 ) x Ti 1-x ]O 3 Thin Films by RF Magnetron Sputtering

1994; Institute of Physics; Volume: 33; Issue: 11R Linguagem: Inglês

10.1143/jjap.33.6301

1347-4065

Ming-Chrong Jiang, Tian-Jue Hong, Tai-Bor Wu Tai-Bor Wu,

Acoustic Wave Resonator Technologies

Ferroelectric Pb[(Mg 1/3 Nb 2/3 ) x Ti 1- x ]O 3 (PMNT) thin films with a well-developed perovskite structure were prepared on Si(100) and Pt/Ti/ SiO 2 /Si(100) substrates by rf magnetron sputtering deposition at high substrate temperatures of 480–650° C. The effect of substrate materials was investigated by X-ray diffraction analysis. The substrates that were topped with a Pt/Ti electrode exhibited a significant effect on reducing the perovskite phase formation temperature of PMNT films; in addition, the TiO 2 rutile phase was found to be formed at the interface between the PMNT film and Pt electrode. It was discovered that the TiO 2 rutile phase would degrade the dielectric and ferroelectric properties of the PMNT films. The 0.5-µm-thick perovskite PMNT films of x =0.3–0.5 exhibited a high dielectric constant ( k ) of 1000–1300, and a dissipation factor less than 0.04 at 1 kHz. Moreover, the films showed satisfactory ferroelectric characteristics. The remanent polarization ( P r ) or coercive field ( E c ) ranged from 23.5 µ C/cm 2 and 82.5 kV/cm, respectively, for 10 PMNT ( x =0.1) to 10.2 µ C/cm 2 and 49 kV/cm for 50 PMNT ( x =0.5) thin films. Due to the formation of a relatively thick TiO 2 interface layer at a high deposition temperature, the 70 PMNT ( x =0.7) films did not show satisfactory dielectric or ferroelectric properties. However, by adding 3 mol% La on the PMNT to reduce the perovskite formation temperature, a 0.5-µm-thick Pb 0.97 La 0.03 Mg 0.235 Nb 0.44 Ti 0.325 O 3 (PLMNT) film was prepared on the Pt/Ti/ SiO 2 /Si substrate, and results of P r =8.5 µ C/cm 2 , E c =46 kV/cm with k =1220 and tan δ<0.04 were obtained.