A High-Performance Mode-Localized Vacuum Gauge Based on FPGA Closed-Loop Control

Vacuum gauges are widely used in semiconductor and industrial equipment. Sensitivity, resolution, and accuracy are the key characteristics of these gauges. The performance of traditional gauge is limited by the size and thickness of the diaphragm, but the thin and large silicon diaphragm is difficult to fabricate. In this paper, mode-localized gauges are developed and operated in a closed-loop configuration. The gauge senses vacuum pressure by a silicon diaphragm, and a weak-coupling resonator is used to measure the deformation of the diaphragm, which can increase the sensitivity compared with traditional resonators. In addition, FPGA-based closed-loop control of the proposed gauge is developed, which is reported for the first time. Three devices are tested from 0.5 to 100 Pa, which can prove the reliability of the design and control strategy. The results show that the performance of the above three devices is improved compared to those of other studies.