Design and Application of MEMS-Based Hall Sensor Array for Magnetic Field Mapping

Chia-Yen Lee,Yu-Ying Lin,Lung-Ming Fu,Chung-Kang Kuo

doi:10.3390/mi12030299

Chia-Yen Lee, Yu-Ying Lin + Show 2 more

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https://doi.org/10.3390/mi12030299

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Abstract

A magnetic field measurement system based on an array of Hall sensors is proposed. The sensors are fabricated using conventional microelectromechanical systems (MEMS) techniques and consist of a P-type silicon substrate, a silicon dioxide isolation layer, a phosphide-doped cross-shaped detection zone, and gold signal leads. When placed within a magnetic field, the interaction between the local magnetic field produced by the working current and the external magnetic field generates a measurable Hall voltage from which the strength of the external magnetic field is then derived. Four Hall sensors are fabricated incorporating cross-shaped detection zones with an identical aspect ratio (2.625) but different sizes (S, M, L, and XL). For a given working current, the sensitivities and response times of the four devices are found to be almost the same. However, the offset voltage increases with the increasing size of the detection zone. A 3 × 3 array of sensors is assembled into a 3D-printed frame and used to determine the magnetic field distributions of a single magnet and a group of three magnets, respectively. The results show that the constructed 2D magnetic field contour maps accurately reproduce both the locations of the individual magnets and the distributions of the magnetic fields around them.

Highlights

Hall sensors based on CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology are widely applied in the manufacturing, medical devices, consumer electronics, automobile, and aerospace fields nowadays due to their low cost, high integration ability, and good reliability [1,2,3,4,5,6,7]
Whenaacurrent currentpassing passingthrough througha semiconductor a semiconductor material flows a direction perWhen material flows in aindirection perpenpendicular to that of an external magnetic field, the carriers in the semiconductor are dedicular to that of an external magnetic field, the carriers in the semiconductor are deflected flected to one and aproduce potential difference called the Hall voltage with a to one side and side produce potentiala difference called the Hall voltage with a magnitude magnitude equal to: equal to: VH =VI =
The excommenced by measuring the voltage response of the four sensors given different working periments commenced by measuring the voltage response of the four sensors given difcurrents (2, 7, and 10 mA) and magnetic field strengths in the range of 0–5200 Gauss

Summary

Introduction

Hall sensors based on CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology are widely applied in the manufacturing, medical devices, consumer electronics, automobile, and aerospace fields nowadays due to their low cost, high integration ability, and good reliability [1,2,3,4,5,6,7]. Hall sensors have many practical advantages, including noncontact operation, high linearity, physical sturdiness, and versatility [8,9,10]. As a result, they have attracted significant attention throughout industry and academia in recent years [11,12,13]. Many sensor fusion techniques have been developed to improve sensing field mapping [14,15]. Such systems could be used for condition monitoring and prognosis of machines [16,17].

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