Monolithically integrated tri-axis shock accelerometers with MHz-level high resonant-frequency

• Published in: Journal of micromechanics and microengineering 2017-07, Vol.27 (7), p.75009
• Main Authors: Zou, Hongshuo, Wang, Jiachou, Chen, Fang, Bao, Haifei, Jiao, Ding, Zhang, Kun, Song, Zhaohui, Li, Xinxin
• Format: Article
• Language: English
• Subjects: high resonant frequency; high-shock; monolithic tri-axis accelerometer; piezoresistance; single-wafer fabrication
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/1361-6439/aa70c1

This paper reports a novel monolithically integrated tri-axis high-shock accelerometer with high resonant-frequency for the detection of a broad frequency-band shock signal. For the first time, a resonant-frequency as high as about 1.4 MHz is designed for all the x-, y- and z-axis accelerometers of the integrated tri-axis sensor. In order to achieve a wide frequency-band detection performance, all the three sensing structures are designed into an axially compressed/stretched tiny-beam sensing scheme, where the p  +  -doped tiny-beams are connected into a Wheatstone bridge for piezoresistive output. By using ordinary (1 1 1) silicon wafer (i.e. non-SOI wafer), a single-wafer based fabrication technique is developed to monolithically integrate the three sensing structures for the tri-axis sensor. Testing results under high-shock acceleration show that each of the integrated three-axis accelerometers exhibit about 1.4 MHz resonant-frequency and 0.2-0.4 µV/V/g sensitivity. The achieved high frequencies for all the three sensing units make the tri-axis sensor promising in high fidelity 3D high-shock detection applications.