Issues in path toward low cost three-axis accelerometer for low-g application

Abstract

The paper presents issues for an optimized three-axis accelerometer implementation. A VerilogA model was built for sensor design, the overall sensitivity, noise and frequency response are obtained by co-simulation with circuit tools. The critical parameters were optimized by theoretical calculation and fine tuned by finite-element-analysis (FEA) and integrated nodal simulation. Three spring-proof mass systems were integrated on a single structure in size of 1.3×1.28mm2 for operating range of ±2g. A silicon-on-glass (SOG) process is adopted to achieve the high aspect-ratio structure, yielding excellent Z-axis sensitivity and resolution as high as 1.434V/g and 49µg/√Hz. The sensitivity and minimum cross-axis sensitivity are 1.442V/g and 0.03% for x-axis and are 1.241V/g and 0.21% for y-axis. This optimized design demonstrates excellent performance satisfying the needs of consumer applications.