Miniature touch mode capacitance vacuum gauge with circular diaphragm

The shape, size, and working state of the pressure-sensing elements are important factors to determine the pressure sensor performances. A touch mode micro-electro-mechanical-system (MEMS) capacitance diaphragm gauge with a circular silicon pressure-sensing diaphragm for vacuum pressure measurement is presented. The diaphragm is designed to work in touch mode, and its basic structure and working principle are introduced. The MEMS capacitance diaphragm gauge has been fabricated, packaged, and tested. The results show that the capacitance-pressure curve has the typical characteristics of touch mode, which is consistent with the original design. The gauge exhibits a good performance in the measurement range of 1 Pa to atmospheric pressure, and the maximum and the minimum sensitivities are 22.16 and 2.39 fF/Pa, respectively. Moreover, the piecewise linear fitting of the capacitance-pressure curve is analyzed.