Design of pressure-sensing diaphragm for MEMS capacitance diaphragm gauge considering size effect

Gang Li,Yongjun Cheng,Detian Li,Xiaodong Han,Wenjun Sun,Chengxiang Wang

doi:10.1063/1.5021374

Abstract

MEMS capacitance diaphragm gauge with a full range of (1∼1000) Pa is considered for its wide application prospect. The design of pressure-sensing diaphragm is the key to achieve balanced performance for this kind of gauges. The optimization process of the pressure-sensing diaphragm with island design of a capacitance diaphragm gauge based on MEMS technique has been reported in this work. For micro-components in micro scale range, mechanical properties are very different from that in the macro scale range, so the size effect should not be ignored. The modified strain gradient elasticity theory considering size effect has been applied to determine the bending rigidity of the pressure-sensing diaphragm, which is then used in the numerical model to calculate the deflection-pressure relation of the diaphragm. According to the deflection curves, capacitance variation can be determined by integrating over the radius of the diaphragm. At last, the design of the diaphragm has been optimized based on three parameters: sensitivity, linearity and ground capacitance. With this design, a full range of (1∼1000) Pa can be achieved, meanwhile, balanced sensitivity, resolution and linearity can be kept.

Highlights

Capacitance diaphragm gauges (CDG) have been widely used in vacuum calibration, space exploration and industrial production etc
Since the first proposing by Hemni et al in 1993,1 a number of CDGs based on Micro-Electro-Mechanical System (MEMS) technology have been designed and manufactured.[2,3,4,5,6,7]
The design of the pressure-sensing diaphragm for a MEMS CDG was optimized under simulated conditions

Summary

Introduction

Capacitance diaphragm gauges (CDG) have been widely used in vacuum calibration, space exploration and industrial production etc. Traditional gauges cannot meet the requirements for vacuum measurement in deep and near space exploration, combat medicine, and strategic weapon because of limitation of volume and weight. Since the first proposing by Hemni et al in 1993,1 a number of CDGs based on MEMS technology have been designed and manufactured.[2,3,4,5,6,7] Nowadays, research on MEMS-type CDGs has become a hot spot in this field. The lower limit of these MEMS-type CDGs is normally larger than 10 Pa, a MEMS CDG with a testing range varying from 1 to 1000 Pa hasn’t been reported. Researches have shown that mechanical properties of micro-component in micro scale range are very different from that in the macro scale range, and the size effect of the mechanical properties for the micro-component has been discovered

Methods

Results

Conclusion