Design considerations and electro-mechanical simulation of an inertial sensor based on a floating gate metal-oxide semiconductor field-effect transistor as transducer

Abstract

In this paper, an analysis on the electrostatic actuation in capacitive complementary metal-oxide semiconductor and micro-electro-mechanical systems (CMOS---MEMS) inertial sensors is presented. These sensors are designed to be used in combination with a floating gate metal oxide semiconductor field-effect transistor as the transducer to convert inertial force to an electrical signal. The effects of connecting micro-sensors with different geometry and having the same mechanic characteristics and integrated electronics for transducing are analyzed. It is shown that the performance of these capacitive structures depends mainly on features like the mechanical properties of the material used and the mechanical behavior given by the geometry. Undesired effects like pitch, roll and yaw movements depend on the geometry and the configuration of the proposed capacitive structure. Also, the biasing of the transducer included in the system affects the electrostatic actuation of the inertial sensor. This study shows that some geometric designs of this kind of sensors may result unreliable for a good transduction when an external force is applied. Furthermore, the proposed design can be fabricated using standard CMOS technologies followed by a sacrificial layer surface micromachining needed for the structure release.