A Three-Axis Magnetic Field Microsensor Fabricated Utilizing a CMOS Process

Abstract

Featured Application: Three-axis magnetic field microsensors in this study can be applied to various electronic instruments, portable electronic devices, mobile phones, and industrial equipment.Abstract: This study develops a three-axis magnetic field (MF) microsensor manufactured by a complementary metal oxide semiconductor (CMOS) process. The MF microsensor contains a ring emitter, four bases, and eight collectors. Sentaurus TCAD was used to simulate the microsensor characterization. The STI (shallow trench isolation) oxide in the process was used to limit the current direction and reduce leakage current. The microsensor produces a voltage difference once it senses a magnetic field. An amplifier circuitry magnifies voltage difference into a voltage output. Experiments reveals that the MF microsensor has a sensitivity of 1.45 V/T along the x-axis and a sensitivity of 1.37 V/T along the y-axis.

Magnetic Micro Sensors with Two Magnetic Field Effect Transistors Fabricated Using the Commercial Complementary Metal Oxide Semiconductor Process

“…The MMS developed by Li [16], Xu [30], and Zhao [31] were 1-axis MF sensors, and the MMS presented by Yang [32] was a 2-axis MF sensor. As shown in Table 1, the sensitivity of the MMS in this work in the x-and y-axis MF exceeded that of Li [16], Tseng [20], and Kimura [26]. The sensitivity of the MMS presented by Tseng [20] in the z-axis MF was lower than that of this work.…”

“…A chopper-stabilized magnetic field effect transistor was employed to design the MMS and to enhance the sensing resolution of the MMS. A three-axis MMS, proposed by Tseng [20], was made using a standard CMOS process. The MMS was a magnetotransistor that included eight collectors, four bases, and a ring emitter.…”

Micro Magnetic Field Sensors Manufactured Using a Standard 0.18-μm CMOS Process

“…The MMF sensors presented by Tseng [ 15 ], Xu [ 20 ] and Zhao [ 21 ] were one-axis MF sensing, and the sensors proposed by Yu [ 17 ], Sung [ 18 ] and Yang [ 22 ] were two-axis MF sensing. As depicted in Table 1 , the sensitivity of the MMF sensor in this work along the x- and y-axis MF exceeds that of Tseng [ 16 ], Yu [ 17 ], Sung [ 18 ] and Yang [ 22 ]. The sensitivity of the sensor presented by Zhao [ 21 ] along the z-axis MF is higher than that of this work.…”

“…The MMF sensor had a sensitivity of 354 mV/T. Furthermore, Tseng [ 16 ] adopted the same method to design a three-axis magnetotransistor MMF sensor that was also made using a standard 0.18-μm CMOS process of TSMC. The MMF sensor had a sensitivity of 6.5 mV/T in the x-axis and a sensitivity of 0.4 mV/T in the y-axis.…”

“…These micro sensors [ 15 , 17 , 20 , 21 , 22 ] manufactured using CMOS technology were one-axis and two-axis MMF sensors. Therefore, three-axis MMF sensors in this work are fabricated using a standard 0.18-μm CMOS process of TSMC, and the sensitivity of the sensors is higher than that of Tseng [ 16 ].…”