Fabrication Technology and Characteristics Research of the Acceleration Sensor Based on Li-Doped ZnO Piezoelectric Thin Films

Sen Li; Xiaofeng Zhao; Yinan Bai; Yi Li; Chunpeng Ai; Dianzhong Wen

doi:10.3390/mi9040178

Fabrication Technology and Characteristics Research of the Acceleration Sensor Based on Li-Doped ZnO Piezoelectric Thin Films

Micromachines (Basel). 2018 Apr 12;9(4):178. doi: 10.3390/mi9040178.

Authors

Sen Li¹, Xiaofeng Zhao², Yinan Bai³, Yi Li⁴, Chunpeng Ai⁵, Dianzhong Wen⁶

Affiliations

¹ Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. 2161311@s.hlju.edu.cn.
² Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. zhaoxiaofeng@hlju.edu.cn.
³ Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. 2141207@s.hlju.edu.cn.
⁴ Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. 2171256@s.hlju.edu.cn.
⁵ Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. 2011026@hlju.edu.cn.
⁶ Key Laboratory of Electronics Engineering, College of Heilongjiang Province, Heilongjiang University, Harbin 150080, China. wendianzhong@hlju.edu.cn.

Abstract

An acceleration sensor based on piezoelectric thin films is proposed in this paper, which comprises the elastic element of a silicon cantilever beam and a piezoelectric structure with Li-doped ZnO piezoelectric thin films. The Li-doped ZnO piezoelectric thin films were prepared on SiO₂/Si by radio frequency (RF) magnetron sputtering method. The microstructure and micrograph of ZnO piezoelectric thin films is analysed by a X-ray diffractometer (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and piezoresponse force microscopy (PFM), respectively. When the sputtering power of 220 W and Li-doped concentration of 5%, ZnO piezoelectric thin films have a preferred (002) orientation. The chips of the sensor were fabricated on the <100> silicon substrate by micro-electromechanical systems (MEMS) technology, meanwhile, the proposed sensor was packaged on the printed circuit board (PCB). The experimental results show the sensitivity of the proposed sensor is 29.48 mV/g at resonant frequency (1479.8 Hz).

Keywords: Li-doped ZnO thin films; MEMS technology; acceleration sensor; piezoelectric thin films.