Design of sub-1g microelectromechanical systems accelerometers

Abstract

This paper presents a design of microelectromechanical systems (MEMS) accelerometers for sensing sub-1g (g = 9.8 m/s2) acceleration. The accelerometer has a high-density proof mass to suppress the Brownian noise that dominates the output noise of the sensor. The low-temperature (<400 °C) process enables to integrate the accelerometer on the sensing complementary metal-oxide semiconductor circuit by electroplating of gold; a proof mass of 1020 μm × 1020 μm in area with the thickness of 12 μm has been found to suppress the measured noise floor to 0.78 μg/Hz at 300 K, which is nearly one order of magnitude smaller than those of the conventional MEMS accelerometers made of silicon.

A 0.18-µm CMOS time-domain capacitive-sensor interface for sub-1mG MEMS accelerometers

“…Fig. 8 schematizes the sub-1mG MEMS accelerometer [6,7]. The proof-mass is shifted by an acceleration input, thereby changing the capacitance between the proof-mass and the fixed electrode.…”

“…Next, the capacitance-frequency characteristics were investigated using an LCR meter (IM3533-01, HIOKI E.E. Corp.), and the B n was evaluated from an analytical model [6]. The values of resonant frequency f res and the quality factor Q were 324 Hz and 2.15, respectively.…”

“…To extend the range of applications, the MEMS accelerometer and interface should achieve high resolution within a small device. In the pursuit of a low-noise MEMS accelerometer, capacitive MEMS accelerometers with gold proof masses were fabricated using multi-layer metal technology [6,7]. Capacitive-sensor interfaces with low noise and a simple structure are required to counterpart the capacitance values of a MEMS accelerometer.…”

Brittle Fracture of Electrodeposited Gold Observed by Micro-Compression

“…These properties make gold promising materials to be used as structure materials in micro-electro-mechanical systems (MEMS) devices. Yamane et al reported that the sensitivity of MEMS accelerometers using gold-based components would be higher when compared with the conventional silicon-based components [1][2][3] . The high sensitivity is mostly contributed by the much higher density of gold (19.30 g/cm 3 at 298 K) than silicon (2.33 g/ cm 3 at 298 K).…”

A micromachined angular-acceleration sensor for geophysical applications

“…6 However, MEMS sensors for geophysical applications are emerging in the past two decades. MEMS seismic-grade accelerometers [7][8][9] have been developed to determine the surface seismic waves for either monitoring earthquakes or subsurface imaging oil exploration using the seismic reflection method, 10 including the 0.2 ng/ ffiffiffiffiffiffi Hz p short-period seismometer 11,12 recently developed in our group as a contribution to NASA's InSight Mars mission. There are also several reported MEMS angular accelerometers.…”