Numerical study on response time of a parallel plate capacitive polyimide humidity sensor based on microhole upper electrode

Wenhe Zhou; Xuan He; Jianyun Wu; Liang-Bi Wang; Liangcheng Wang

doi:10.1117/1.JMM.16.3.034502

4 August 2017 Numerical study on response time of a parallel plate capacitive polyimide humidity sensor based on microhole upper electrode

Wenhe Zhou, Xuan He, Jianyun Wu, Liang-Bi Wang, Liangcheng Wang

Author Affiliations +

Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 16, Issue 3, 034502 (August 2017). https://doi.org/10.1117/1.JMM.16.3.034502

Abstract

The parallel plate capacitive humidity sensor based on the grid upper electrode is considered to be a promising one in some fields which require a humidity sensor with better dynamic characteristics. To strengthen the structure and balance the electric charge of the grid upper electrode, a strip is needed. However, it is the strip that keeps the dynamic characteristics of the sensor from being further improved. The numerical method is time- and cost-saving, but the numerical study on the response time of the sensor is just of bits and pieces. The numerical models presented by these studies did not consider the porosity effect of the polymer film on the dynamic characteristics. To overcome the defect of the grid upper electrode, a new structure of the upper electrode is provided by this paper first, and then a model considering the porosity effects of the polymer film on the dynamic characteristics is presented and validated. Finally, with the help of software FLUENT, parameter effects on the response time of the humidity sensor based on the microhole upper electrode are studied by the numerical method. The numerical results show that the response time of the microhole upper electrode sensor is 86% better than that of the grid upper electrode sensor, the response time of humidity sensor can be improved by reducing the hole spacing, increasing the aperture, reducing film thickness, and reasonably enlarging the porosity of the film.

Citation Download Citation

Wenhe Zhou, Xuan He, Jianyun Wu, Liang-Bi Wang, and Liangcheng Wang "Numerical study on response time of a parallel plate capacitive polyimide humidity sensor based on microhole upper electrode," Journal of Micro/Nanolithography, MEMS, and MOEMS 16(3), 034502 (4 August 2017). https://doi.org/10.1117/1.JMM.16.3.034502

Received: 23 February 2017; Accepted: 10 July 2017; Published: 4 August 2017

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