Implementation of a CMOS/MEMS Accelerometer with ASIC Processes.

Yu-Sian Liu,Kuei-Ann Wen

doi:10.3390/mi10010050

Yu-Sian Liu, Kuei-Ann Wen

Open Access

https://doi.org/10.3390/mi10010050

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Journal: Micromachines	Publication Date: Jan 12, 2019
Citations: 9	License type: CC BY 4.0

Affiliation: National Yang Ming Chiao Tung University

Abstract

This paper presents the design, simulation and mechanical characterization of a newly proposed complementary metal-oxide semiconductor (CMOS)/micro-electromechanical system (MEMS) accelerometer. The monolithic CMOS/MEMS accelerometer was fabricated using the 0.18 μm application-specific integrated circuit (ASIC)-compatible CMOS/MEMS process. An approximate analytical model for the spring design is presented. The experiments showed that the resonant frequency of the proposed tri-axis accelerometer was around 5.35 kHz for out-plane vibration. The tri-axis accelerometer had an area of 1096 μm × 1256 μm.

Highlights

Micro-electromechanical system (MEMS) technology has enabled the substantial expansion of the inertial sensor market by decreasing power consumption, cost, and size
The complementary metal-oxide semiconductor (CMOS)/micro-electromechanical system (MEMS) technology enables the integration of CMOS circuits with MEMS structures in a single chip [1]
CMOS/MEMS processes have the advantages of a mature foundry service for mass production, monolithic integration with CMOS circuitry to reduce the parasitic capacitance, and size reduction to decrease chip cost [2,3,4,5,6,7]

Summary

Introduction

Micro-electromechanical system (MEMS) technology has enabled the substantial expansion of the inertial sensor market by decreasing power consumption, cost, and size. The composite thin-film structure of CMOS/MEMS technology suffers from residual stresses and limits the device’s performance. A capacitive accelerometer can be implemented in the CMOS/MEMS process [10]. A capacitive CMOS/MEMS accelerometer typically consists of the proof-mass, springs, and sensing electrodes. A single proof-mass tri-axis accelerometer can significantly reduce the chip size and improve the accelerometer sensitivity [15,16]. The design, simulation and mechanical characterization of the proposed CMOS/MEMS accelerometer is presented. The 0.18 μm application-specific integrated circuit (ASIC)-compatible CMOS/MEMS process was adopted for sensor and circuit implementation.

Process Flow

Design

Tri-Axis Accelerometer

Results

Discussion and Conclusions