Manufacturing and Characterization of Three-Axis Magnetic Sensors Using the Standard 180 nm CMOS Technology.

Chi-Han Wu,Ching-Liang Dai,Po-Jen Shih,Yao-Chuan Tsai

doi:10.3390/s21216953

Abstract

A three-axis micro magnetic sensor (MS) is developed based on the standard 180 nm complementary metal oxide semiconductor (CMOS) technology. The MS designs two magnetic sensing elements (MSEs), which consists of an x/y-MSE and an z-MSE, to reduce cross-sensitivity. The x/y-MSE is constructed by an x-MSE and an y-MSE that are respectively employed to detect in the x- and y-direction magnetic field (MF). The z-MSE is used to sense in the z-direction MF. The x/y-MSE, which is constructed by two magnetotransistors, designs four additional collectors that are employed to increase the sensing current and to enhance the sensitivity of the MS. The Sentaurus TCAD software simulates the characteristic of the MS. The measured results reveal that the MS sensitivity is 534 mV/T in the x-direction MF, 525 mV/T in the y-direction MF and 119 mV/T in the z-axis MF.

Highlights

TCAD software simulates the characteristic of the magnetic sensor (MS)
The MS was composed of an x/y-magnetic sensing elements (MSEs) and a z-MSE, where the z-MSE detected the magnetic field (MF) in the z-direction and the x/y-MSE sensed the MF in the xand y-direction
The x/y-MSE, which consisted of two magnetotransistors, designed four additional collectors that enhanced the mobility of carriers in the p-substrate and increased the MS sensitivity

Summary

Introduction

TCAD software simulates the characteristic of the MS. The measured results reveal that the MS sensitivity is 534 mV/T in the x-direction MF, 525 mV/T in the y-direction MF and 119 mV/T in the z-axis MF. Magnetic sensors (MSs) have a wide range of uses and can be applied in control and monitoring devices, industrial products, material testing, manufacturing systems and biomedical engineering. Oh [3] adopted a small magnet, an MEMS MS and a breathing output component to compose a respiratory monitoring and training system that was used to train and monitor the breath of patients for radiotherapy. Lara-Castro [4] employed a micromachined MS to constitute a portable signal conditioning system for industrial applications to measure ferromagnetic material characteristic. The MEMS technology was adopted to design and fabricate various micro MSs. Table 1 summarizes the sensing principle and type for various micro magnetic sensors. The magnetic sensing material for the sensor was the copper-based amorphous wire.

Methods

Results

Conclusion