Pillar-Shaped Electrodes for 3-axis Gold-Proof-Mass MEMS Capacitive Accelerometers

This paper reports pillar-shaped capacitance-detection electrodes for 3-axis MEMS accelerometers with a gold proof mass. The proposed electrode structure allows us to easily release sacrificial layers when compared with conventional ones, such as parallel-plate and comb electrodes. Thanks to the high-degree of freedom in the electrode layout, the pillar-shaped electrode could also be useful to increase the X/Y-axis capacitance sensitivities in 3-axis MEMS accelerometers with a single proof mass. In this work, we present the design, fabrication and experimental results of the pillar-shaped electrode applied to a 3-axis gold-proof-mass MEMS capacitive accelerometer. A proof-of-concept device is developed by a MEMS foundry process. The measured characteristics are found to be consistent with the designed ones.