Polewczyk Vincent, Magrin Maffei Riccardo, Vinai Giovanni, Lo Cicero Matteo, Prato Stefano, Capaldo Pietro, Dal Zilio Simone, di Bona Alessandro, Paolicelli Guido, Mescola Andrea, D'Addato Sergio, Torelli Piero, Benedetti Stefania
Laboratorio TASC, Istituto Officina dei Materiali (IOM)-CNR, 34149 Trieste, Italy.
Istituto Nanoscienze-CNR, Via Campi 213/a, 41125 Modena, Italy.
Sensors (Basel). 2021 Sep 12;21(18):6114. doi: 10.3390/s21186114.
The piezoelectric response of ZnO thin films in heterostructure-based devices is strictly related to their structure and morphology. We optimize the fabrication of piezoelectric ZnO to reduce its surface roughness, improving the crystalline quality, taking into consideration the role of the metal electrode underneath. The role of thermal treatments, as well as sputtering gas composition, is investigated by means of atomic force microscopy and x-ray diffraction. The results show an optimal reduction in surface roughness and at the same time a good crystalline quality when 75% O is introduced in the sputtering gas and deposition is performed between room temperature and 573 K. Subsequent annealing at 773 K further improves the film quality. The introduction of Ti or Pt as bottom electrode maintains a good surface and crystalline quality. By means of piezoelectric force microscope, we prove a piezoelectric response of the film in accordance with the literature, in spite of the low ZnO thickness and the reduced grain size, with a unipolar orientation and homogenous displacement when deposited on Ti electrode.
基于异质结构的器件中ZnO薄膜的压电响应与其结构和形态密切相关。考虑到下方金属电极的作用，我们优化了压电ZnO的制备工艺，以降低其表面粗糙度，提高晶体质量。通过原子力显微镜和X射线衍射研究了热处理以及溅射气体成分的作用。结果表明，当溅射气体中引入75%的O且在室温至573K之间进行沉积时，表面粗糙度得到了最佳降低，同时晶体质量良好。随后在773K下退火进一步提高了薄膜质量。引入Ti或Pt作为底部电极可保持良好的表面和晶体质量。通过压电力显微镜，我们证明了尽管ZnO薄膜厚度较低且晶粒尺寸减小，但根据文献，该薄膜仍具有压电响应，沉积在Ti电极上时具有单极取向和均匀位移。
