A 1 mG lateral CMOS-MEMS accelerometer

Abstract

This paper reports a lateral CMOS-MEMS accelerometer with a measured noise floor of 1 mG//spl radic/(Hz) and a dynamic range larger than 13 G. The accelerometer is fully compatible with conventional CMOS processes enabling the integration of most of the conditioning circuits. It is fabricated in a three metal layer 0.5 /spl mu/m CMOS process followed by a two-step dry etch release. An improved curl matching technique is utilized to solve the out-of-plane curl problem. A new differential amplifier is used for the capacitive sensing interface. The CMOS micromachining process used in this project is described. The design of accelerometer, system schematic applying force-balance feedback and experimental test results are presented.