Browsing by Author "Duan, Hao"

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A Novel MEMS DC Magnetic Sensor Using Thermomagnetic-Piezoelectric Materials with a Coil-Less Reset Approach
(2018-01-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
We report a novel MEMS DC magnetic sensor using thermomagnetic-piezoelectric materials with a coil-less magnetization-reset approach. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) sheet. Due to the Gd's thermomagnetic property, the sensor at low temperature (for instant, 9 degrees C.; below its Curie temperature which is in room temperature range) can sense ambient DC magnetic fields. Without using on-chip coils, the sensor can be easily reset by heating the sensor higher than its Curie temperature (for example, 45 degrees C. According to experimental results, the sensor successfully senses DC magnetic field from 2 to 100 Gauss and is 45 degrees C. When comparing to conventional NEMS, MEMS, and AMR magnetic sensors (i.e., using magnetic materials requiring on-chip magnetization-reset coils which occupy huge chip footprint), our sensor with the coil-less reset approach can significantly reduce the sensor footprint.
A NOVEL SELF-POWERED PIEZOELECTRIC THREE-AXIS MEMS MAGNETIC SENSOR
(2017-01-01)
Yeh, Po-Chen
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
This paper demonstrates a self-powered piezoelectric three-axis MEMS magnetic sensor. The sensor consists of a silicon diaphragm, a PZT thin film with Pt top and bottom electrodes, and two patterned Ni thick films. When three-axial magnetic fields are applied to the sensor, alternating magnetic forces/torques are induced in two Ni films and consequently corresponding deformation/bending are produced in the diaphragm structure. The deformation/bending of the diaphragm generate the strains in the PZT thin film and thus produce corresponding different piezoelectric voltage responses. The testing results show the sensor successfully senses three-axial magnetic fields and has a decent linearity in the range of 5-70 Gauss.
A Novel Three-Axial Magnetic-Piezoelectric MEMS AC Magnetic Field Sensor
(2019-10-01)
Yeh, Po-Chen
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
We report a novel three-axial magnetic-piezoelectric microelectromechanical systems (MEMS) magnetic field sensor. The sensor mainly consists of two sensing elements. Each of the sensing elements consists of a magnetic Ni thick film, a Pt/Ti top electrode, a piezoelectric lead zirconate titanate (PZT) thin film, a Pt/Ti bottom electrode, a SiO2 insulation layer, and a moveable Si MEMS diaphragm. When the sensor is subjected to an AC magnetic field oscillating at 7.5 kHz, a magnetic force interaction between the magnetic field and Ni thick film is produced. Subsequently, the force deforms and deflects the diaphragms as well as the PZT thin film deposited on the diaphragms. The deformation and deflection produce corresponding voltage outputs due to the piezoelectric effect. By analyzing the voltage outputs through our criterion, we can obtain details of the unknown magnetic fields to which the sensor is subjected. This achieves sensing of three-axial magnetic fields. The experimental results show that the sensor is able to sense three-axial magnetic fields ranging from 1 to 20 Oe, with X-axial, Y-axial, and Z-axial sensitivities of 0.156 mV(rms)/Oe, 0.156 mV(rms)/Oe, and 0.035 mV(rms)/Oe, respectively, for sensing element A and 0.033 mV(rms)/Oe, 0.044 mV(rms)/Oe, and 0.130 mV(rms)/Oe, respectively, for sensing element B.
A thermomagnetic-piezoelectric MEMS AC magnetic-field sensor demonstrating a novel room-temperature-range coil-less resetting/demagnetizing approach
(2019-10-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Tseng, Chia-Yung
;
Chung, Tien-Kan
We report a novel thermomagnetic-piezoelectric MEMS AC magnetic-field sensor. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) film covered by a Pt anti-oxidation layer. Due to the thermomagnetic-Gd/piezoelectric-PZT layered structure, the sensor not only can sense AC magnetic field, but also can be reset/demagnetized automatically at temperature higher than Gd's Curie temperature which is in room-temperature range. Experimental results show that the sensor successfully senses AC magnetic field from 1 to 14 Gauss at 9 degrees C, and is automatically reset/demagnetized at 45 degrees C. While conventional MEMS and AMR magnetic sensors using magnetic materials require on-chip resetting/demagnetizing coils which need a huge footprint of the chip, our sensor utilizing the coil-less resetting/demagnetizing approach significantly reduces the sensor footprint. In the other hand, when comparing to conventional coil-less resetting/demagnetizing method (i.e., annealing magnetic material at hundreds degrees C), our coil-less resetting/demagnetizing approach is at room-temperature range (for instant, 45 degrees C). (C) 2019 Elsevier B.V. All rights reserved.
THERMOMAGNETIC MICRO-TRACKS-GUIDED MAGNETIC BEAD MANIPULATION: A DEMONSTRATION OF MOVING BEAD ACROSS DIFFERENT TRACKS ENABLED BY NOVEL EMBEDDED ON-CHIP MICRO HEATING WIRES
(2019-01-01)
Fang, Lin-Huei
;
Duan, Hao
;
Chen, Chin-Chung
;
Cheng, Chin-Cheng
;
Chung, Tien-Kan
In this paper, we show a demonstration of moving bead across different tracks enabled by novel embedded on-chip micro heating wires for thermomagnetic micro-tracks-guided magnetic bead manipulation. The demonstration includes a magnetic-bead-manipulation chip (which consists of thermomagnetic NiCu micro-disk tracks deposited on top of on-chip platinum micro heating wires fabricated on top of a silicon substrate), a magnetic bead, a thermoelectric generator (TEG), a pulse-generation circuit, and four external electromagnets. Because curie temperature of the track is approximate in room-temperature range, when we apply a pulse current to the heating wires to individually heat the track higher than room temperature, the magnetic property of the track is switched to paramagnetic. Oppositely, when we apply a current to TEG to cool the track lower than room temperature, the track is switched to ferromagnetic. By sequentially/selectively heating or cooling the tracks to switch the tracks to paramagnetic or ferromagnetic, together with applying directional magnetic field, we can achieve moving bead across different NiCu micro-disk tracks. This is an important and significant progress for conventional thermomagnetic micro-tracks-guided magnetic bead manipulation which cannot demonstrate moving bead across different tracks. Therefore, our approach provides a new and complete thermomagnetic micro-tracks-guided magnetic bead manipulation for lab-on-chip micro systems and biomedical MEMS/NEMS.
Three-axis MEMS DC magnetic sensor using magnetic force interaction with the piezoelectric effect
(2018-01-01)
Yeh, Po-Chen
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
;
國際半導體學院
In this paper, we report a novel three-axis MEMS DC magnetic sensor using magnetic force interaction and piezoelectric effect. The sensor includes a back-side-etched silicon diaphragm, a sol-gel PZT thin film with electrodes, and two patterned electroplated Ni thick films. Each patterned Ni film has specific magnetization direction, defined as specific sensing area. As a DC magnetic fields is applied to the sensor, impulse magnetic force and torque are induced to deflect and twist specific Ni films, respectively. Through the mechanical coupling between the Ni films and the PZT film, the deflection and bending are transmitted to the PZT film to produce piezoelectric peak voltages. Experimental results show that, by analysing full duration and half maximum of voltage outputs produced in two sensing areas, the sensor is able to sense three-axial DC magnetic fields.