Dynamic Sensitivity Study of MEMS Capacitive Acceleration Transducer Based on Analytical Squeeze Film Damping and Mechanical Thermoelasticity Approaches

TL;DR

This paper presents a theoretical analysis of a MEMS capacitive accelerometer's dynamic behavior, incorporating squeeze film damping and thermoelastic effects, across various temperatures and pressures, with validation against experimental data.

Contribution

It introduces a comprehensive analytical model combining SFD and thermoelasticity for MEMS accelerometers, considering different gases and environmental conditions.

Findings

Damping gas type significantly affects device damping and sensitivity.

The model accurately predicts dynamic sensitivity across temperature and pressure ranges.

Results align well with experimental measurements, validating the theoretical approach.

Abstract

The dynamic behavior of a capacitive micro-electro-mechanical (MEMS) accelerometer is evaluated by using a theoretical approach which makes use of a squeeze film damping (SFD) model and ideal gas approach. The study investigates the performance of the device as a function of the temperature, from 228 K to 398 K, and pressure, from 20 to 1000 Pa, observing the damping gas trapped inside de mechanical transducer. Thermoelastic properties of the silicon bulk are considered for the entire range of temperature. The damping gases considered are Air, Helium and Argon. The global behavior of the system is evaluated considering the electro-mechanical sensitivity (SEM) as the main figure of merit in frequency domain. The results show the behavior of the main mechanism losses of SFD, as well as the dynamic sensitivity of the MEMS transducer system, and are in good agreement with experimental dynamic results behavior.