A prototype design for an accelerometer using a multiple floating-gate MOSFET as a transducer

Abstract

In this work, a design for a high G sensor is proposed demonstrating a novel transduction technique that can be fabricated with a standard 0.5μm CMOS technology. No additional modifications to the fabrication steps are needed to achieve a MEMS (Micro-Electro-Mechanical System) accelerometer. The proposed system uses Multiple Input Floating-gate MOS transistors (MIFGMOS) as capacitive transduction elements. A variable capacitance is configured between fingers attached to the proof mass as one plate, and to the fixed structure, as the other plate. When acceleration is applied, this results in a modification of the floating gate voltage of the FGMOS, with a corresponding current change that can be correlated to acceleration. Also, a mechanical study was made with a given geometry structure, as well as an electrical analysis of the FGMOS transistor performance. Finally, a layout is proposed for the accelerometer system. Therefore, it is demonstrated that this design can be fabricated with the desired specifications through a standard CMOS technology. Additionally a novel transduction alternative compared to that used in conventional designs is demonstrated.