Department of Electronics Engineering, Chang Gung University, Taoyuan, 33302, Taiwan.
Division of Urology, Chang Gung Memorial Hospital, Taoyuan, 33305, Taiwan.
Sci Rep. 2018 Aug 27;8(1):12902. doi: 10.1038/s41598-018-30993-7.
In this study we developed ytterbium tantalum oxide (YbTaO) sensing membranes for use in electrolyte-insulator-semiconductor (EIS) pH sensors. The influence of rapid thermal annealing (RTA) treatment on the sensing and impedance properties of the YbTaO sensing membranes deposited through reactive co-sputtering onto Si substrates was explored. X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy revealed the structural, morphological, and chemical features, respectively, of these YbTaO films annealed at 700, 800 and 900 °C. The YbTaO EIS device annealed at the 800 °C exhibited a super-Nernstian response of 71.17 mV/pH within the pH range of 2-12. It also showed the lowest hysteresis voltage ( < 1 mV) and the lowest drift rate (0.22 mV/h) among the tested systems. Presumably, the optimal annealing temperature improved the stoichiometry of YbTaO film and increased its (-131)-oriented nanograin size. Moreover, the impedance properties of YbTaO EIS sensors were investigated by using the capacitance-voltage method. The resistance and capacitance of YbTaO sensing films annealed at three various temperatures were evaluated by using different frequency ranges in accumulation, depletion, and inversion regions. The semicircle diameter of the YbTaO EIS sensor became smaller, due to a gradual decrease in the bulk resistance of the EIS device, as the RTA temperature was increased.
在这项研究中，我们开发了掺镱钽酸氧化物（YbTaO）传感膜，用于电解质-绝缘体-半导体（EIS）pH 传感器。通过反应共溅射在 Si 衬底上沉积的 YbTaO 传感膜的快速热退火（RTA）处理对传感和阻抗特性的影响进行了探讨。X 射线衍射、原子力显微镜和 X 射线光电子能谱分别揭示了这些在 700、800 和 900°C 下退火的 YbTaO 薄膜的结构、形貌和化学特征。在 pH 值为 2-12 的范围内，在 800°C 下退火的 YbTaO EIS 器件表现出超 Nernst 响应，响应值为 71.17 mV/pH。它还表现出测试系统中最低的滞后电压（<1 mV）和最低的漂移率（0.22 mV/h）。据推测，最佳退火温度改善了 YbTaO 薄膜的化学计量比，并增加了其 (-131) 取向纳米晶粒尺寸。此外，还通过电容-电压法研究了 YbTaO EIS 传感器的阻抗特性。通过在积累、耗尽和反型区域中使用不同的频率范围，评估了在三种不同温度下退火的 YbTaO 传感薄膜的电阻和电容。随着 RTA 温度的升高，EIS 器件的体电阻逐渐减小，导致 YbTaO EIS 传感器的半圆直径变小。
