Miniature capacitance diaphragm gauge for absolute vacuum measurement. (15th May 2022)

• Record Type: Journal Article
• Authors: Han, Xiaodong; Li, Gang; Xu, Mahui; Guo, Chaomao; Wang, Yongjun; Feng, Yongjian; Li, Detian
• Is Part Of: Measurement. Volume 194(2022)
• Publication Date: 2022-05-15
• Subjects: Miniature -- Vacuum gauge -- Diaphragm -- Capacitance; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2022.110851
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: A MEMS capacitance diaphragm gauge is developed for measuring absolute vacuum pressure in the range of 0.1 Pa to atmospheric pressure. A novel glass-silicon-glass structure is proposed to simplify the fabrication processes and improve the vacuum sealing performance. Touch mode structure and non-evaporable getter films are used to protect the diaphragm and maintain the high vacuum in the reference cavity. The maximum sensitivity of the gauge is 10.96 fF/Pa, meanwhile, good repeatability, hysteresis and long-term stability are also exhibited. Abstract: Miniaturization of sensors using micromachining technology is full of potential and challenges. A miniature capacitance diaphragm gauge for absolute vacuum measurement is developed in this work. Both theoretical calculation and simulation method are used to analyze the working principle of the pressure sensitive diaphragm in different pressure regions. During the manufacturing processes, a silicon block coated with non-evaporable getter films is used to protect the diaphragm and maintain the vacuum pressure of the reference cavity. The capacitance diaphragm gauge with an overall size of 8 × 10 × 1.4 mm 3 was successfully fabricated, and its vacuum metrologies in rough and medium vacuum regime were evaluated systematically. The lower measurement limit of the gauge is 0.1 Pa, its maximum and minimum sensitivities in the range of 0.1 Pa to 84 kPa are 10.96 and 0.16 fF/Pa, respectively. The repeatability and the hysteresis errors of the gauge are less than 1.3% and 5.3%.