Single-axis gold micro-electro-mechanical-systems capacitive accelerometer with circular proof-mass for suppressing warpage

Abstract This paper describes the structural stability and device characteristics of a single-axis gold proof-mass micro-electro-mechanical-systems (MEMS) capacitive accelerometer fabricated using Ti/Au multilayer metal technology. We propose a circular proof-mass structure to suppress warping deformation of the proof-mass caused by the mismatch in thermal expansion coefficients between Ti and Au. The measured warpage of the fabricated device is less than 1% related to the proof-mass radius. The MEMS capacitive accelerometer shows a valid capacitance–voltage ( C – V ) response characteristic due to warpage suppression. The experimental measurements determine its sensitivity and Brownian noise at 2.3 pF g −1 and 0.17 μ g Hz −1/2 , respectively. These values satisfy the specification for the detection of μ g -level acceleration. It is confirmed that the use of the circular proof-mass structure for the MEMS capacitive accelerometers realizes its structural stability with high sensitivity.