A novel SOI-MEMS ‘Micro- Swing’ time-accelerometer operating in two time-based transduction modes for high sensitivity and extended range

Abstract

Here we report the design, modelling, fabrication and initial characterisation results of a new SOI-MEMS “micro-swing” time-accelerometer. Time-based acceleration sensing can be performed using either the embedded piezoresistors or the capacitive sense electrodes. The accelerometer can be operated in two distinct time-based transduction modes aimed at high sensitivity and extended operation range, depending on the applied drive voltage (α.VPull-In). A high sensitivity of 0.914μs/μg is achieved using the pull-in time metastable (PITMS) region (for, α = 1.01) over a small acceleration range from ±0.02g-±0.79g. Extended operation range up to ±2g can be achieved through mechanical time-of-flight (TOF) sensing (for, α ≥ 1.4). Preliminary measurements indicate device functionality and a pull-in transit time of 11ms for a tilt-acceleration corresponding to 70mg.