IEEE Trans Ultrason Ferroelectr Freq Control. 2017 Mar;64(3):617-622. doi: 10.1109/TUFFC.2017.2647971. Epub 2017 Jan 4.
The degradation of niobium-doped lead zirconate titanate (PZT) and two types of PZT thin films were investigated. Undoped PZT, two-step PZT, and heavily Nb-doped PZT (PNZT) around the morphotropic phase boundary were in situ deposited under optimum condition by RF-magnetron sputtering. All 2- [Formula: see text]-thick films had dense perovskite columnar grain structure and self-polarized (100) dominant orientation. PZT thin films were deposited on Pt/TiO bottom electrode on Si wafer, and PNZT thin film was on Ir/TiW electrode with the help of orientation control. Sputtered PZT films formed on microelectromechanical system (MEMS) gyroscope and the degradation rates were compared at different temperatures. PNZT showed the best resistance to the thermal degradation, followed by two-step PZT. To clarify the effect of oxygen vacancies on the degradation of the film at high temperature, photoluminescence measurement was conducted, which confirmed that oxygen vacancy rate was the lowest in heavy PNZT. Nb-doping PZT thin films suppressed the oxygen deficit and made high imprint with self-polarization. This defect distribution and high internal field allowed PNZT thin film to make the piezoelectric sensors more stable and reliable at high temperature, such as reflow process of MEMS packaging.
研究了掺铌钛酸铅锆（PZT）和两种 PZT 薄膜的降解情况。在最佳条件下，通过射频磁控溅射原位沉积了未掺杂 PZT、两步 PZT 和近化学计量比掺铌 PZT（PNZT）。所有 2-μm 厚的薄膜均具有致密的钙钛矿柱状晶粒结构和自极化（100）主导取向。PZT 薄膜沉积在 Si 晶片上的 Pt/TiO 底电极上，PNZT 薄膜沉积在 Ir/TiW 电极上，以帮助控制取向。溅射的 PZT 薄膜沉积在微机电系统（MEMS）陀螺仪上，并在不同温度下比较了它们的降解速率。PNZT 表现出对热降解的最佳抗性，其次是两步 PZT。为了阐明高温下氧空位对薄膜降解的影响，进行了光致发光测量，证实了在重掺 PNZT 中氧空位率最低。PZT 薄膜的 Nb 掺杂抑制了氧空位缺陷，并通过自极化产生了高的内电场。这种缺陷分布和高内场使得 PNZT 薄膜在高温下（例如 MEMS 封装的回流过程）使压电传感器更加稳定可靠。
