A CMOS Compatible Micro Pirani Gauge with Structure Optimization for Performance Enhancement

In this paper, we reported a CMOS compatible micro-Pirani gauge using the CMOS compatible fabrication process. For the first time, we revealed that the tiny fluid conduction gap can not only enhance the sensitivity of the device but also can improve the dynamic measurement range, especially in the high-pressure region making it possible to exceed the 1 atm monitoring domain. Firstly, the CFD simulation was conducted to simulate the performance of devices with a tiny gap (T) and large gap (L) and validate the proposed discoveries. Then, a CMOS-compatible fabrication method was created with an overall dry etching method. Finally, the experimental results demonstrated the proposed idea that the T-type device could provide more than two folds higher sensitivity (4.01 μA/Torr) compared with the L-type one (1.63 μA/Torr), and a larger dynamic measurement range was achieved by the T-type gauge (0.01~760 Torr or more) compared with the L-type one (0.01~100 Torr). Besides, the device also showed high stability with a small variation value (3.8‰ @ 1.3e-4 Torr).