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Magnetic GAA (MAG-GAA) for Vertical and Horizontal Magnetic Field Detection
(2024-01-01)
Swe, Khine Thandar Nyunt
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Poyai, Amporn
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Phetchakul, Toempong
The Gate All Around (GAA) is introduced as a magnetic sensor to sense the vertical and horizontal magnetic field applied to the device. Magnetic GAA (MAG-GAA) consisting of one source contact, one gate contact wrapped around the channel, and four drain contacts are created and simulated for the two-dimensional magnetic field detection using Sentaurus. The proposed device structure of MAG-GAA is designed and operated based on the current mode of the Hall effect. The vertical magnetic field is sensed by activating the drain contacts D<inf>1</inf> and D<inf>2</inf>. To detect the horizontal magnetic field, the drain contacts D<inf>3</inf> and D<inf>4</inf> positioned at the top and bottom surfaces of the device are enabled. The differential drain current is obtained as the magnetic response in both detections. MAG-GAA in which the channel length and width are 10 nm and 5 nm respectively is simulated by applying the magnetic field 0.1 T, 0.2 T, 0.3 T, 0.4 T, and 0.5 T in +z, -z, +y, and -y directions. Their respective magnetic responses are illustrated, and the Hall current reaches the highest value at the magnitude of the magnetic field 0.5 T in both cases of magnetic field detection. The sensitivity of MAG-GAA for vertical magnetic field detection is better than its sensitivity for the horizontal magnetic field.
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Contactless silicon-based multi-dimensional Hall sensor with simultaneous magnetic sensing and omni-rotational angle measurement
(2019-01-01)
Kaewjumras, Yongyut
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Prabket, Jirawat
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Titiroongruang, Wisut
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Niemcharoen, Surasak
This experimental research proposes a contactless silicon-based two-dimensional (2D) Hall sensor capable of simultaneous parallel- and perpendicular-directional magnetic sensing, with a 360° angle measurement. The Hall sensor was of non-symmetrical five-ohmic contact configuration (C1 – C5). In the study, experiments were carried out in three stages. In the first-stage experiment, the current (I) and voltage (V) of the 2D Hall sensor were determined under three schemes: schemes A (C1&C2), B (C2&C5), and C (C3&C4). In the second-stage experiment, the parallel and perpendicular absolute sensitivities of the 2D sensor were examined. Considering the discrepancy between the parallel and perpendicular absolute sensitivities, signal conditioning circuitry was incorporated into the sensor system to compensate, and the rotational angles measured in the final-stage experiment. The results revealed that the I-V curves were dominantly linear, corresponding to Ohm’s law. However, the parallel and perpendicular absolute sensitivities were low and unequal. Thus, signal conditioning circuitry was incorporated into the system to address the discrepancy and improve the performance. Importantly, the 2D Hall sensor exhibited a mere ±3o discrepancy between the measured and reference rotational angles, given the magnetic flux density of 1000 G, with the hysteresis error of 2.8%. In essence, the proposed contactless silicon-based 2D Hall sensor possesses high potential for high-precision industrial applications.
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Processing and characterization of amorphous copper oxide thin films prepared by reactive magnetron sputtering
(2018-01-01)
Gaewdang, Thitinai
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Wongcharoen, Ngamnit
In this paper, copper oxide (CuO<inf>x</inf>) thin films with amorphous phase were prepared on glass substrates by reactive dc magnetron sputtering. The influence of the flow rate of O<inf>2</inf> on the structural, optical and electrical properties of the as-deposited films was systematically studied. XRD revealed that the as-deposited films remained amorphous in the whole range of adjusted oxygen flow rate. Surface morphology and nanoparticle size of the films were observed by AFM. Electrical resistivity and Hall effect measurements were performed on the films with van der Pauw configuration. The positive sign of the Hall coefficient confirmed the p-type conductivity in all studied films. From temperature-dependent electrical conductivity of the films prepared at R(O<inf>2</inf>) of 1.5 sccm, it was show that three types of behavior can be expected, nearest-neighbor hopping at high temperature range (200-300 K), the Mott variable range hopping at low temperature (110-190 K) and Efros-Shklovskii variable range hopping at very low temperature (65-100 K). Some important parameters corresponding to Mott-VRH and ES-VRH like density of localized states near the Fermi level (N(E<inf>F</inf>)), localization length (ξ), degree of disorder(T<inf>0</inf>), hopping distance (R) and hopping energy (W) were determined. These parameters would be helpful for optimizing the performance of photovoltaic applications.
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Influence of annealing temperature on the properties of SnS thin films prepared by vacuum thermal evaporation
(2017-01-01)
Wongcharoen, Ngamnit
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Gaewdang, Thitinai
SnS thin films were deposited by thermal evaporation in vacuum on glass slide substrate. The as-deposited films were thermally annealed in a controlled N<inf>2</inf> atmosphere with annealing temperature in the range 100-500°C for 30 min. XRD, AFM, UV-VIS transmittance, FTIR and Hall effect measurements were used for characterization the as-deposited and annealed films. Based on the XRD patterns, the as-deposited and annealed films were indentified as the orthrombic structure. The band gap was found to increase from 1.15 to 1.42 eV when the annealing temperature increased from 100 to 500°C. The lowest resistivity and highest carrier concentration values were observed to be 12.95 Ω. cm and 1.98×1016cm-3on the films annealed at 100 and 200°C, respectively.
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Application of Multi-Dimensional Hall Sensor for Gauss Measurement
(2017-01-01)
Kaewjumras, Yongyut
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Mano, Athirot
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Titiroongruang, Wisut
This paper reported on a two-dimensional Hall sensor enabling to measure the two spatial components of the magnetic field and applied for gauss measurement application. The device was operated through only five contacts and tested by varying the magnetic flux density from -5000 to 5000 Gauss (G) and using signal conditioning circuitry for amplifying and adjusting the both similar sensitivity. After that, the output signals were converted to digital signals by ADC for transmitting a computer using LAB-VIEW programming and comparison with the standard gauss meter (F.W.Bell5170). The result of gauss measuring application comparison with the standard gauss meter has done with a precision of 0.04-3.80% including a calibration process.
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Split-current magnetoresistor
(2013-10-04)
Phetchakul, Toempong
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Taisettavatkul, Prateep
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Yamwong, Wittawat
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Poyai, Amporn
The split-current magnetoresistor is proposed here. The structure likes the series magnetoresistor that one end split into two symmetrical terminals, so it is the magnetoresistor with three terminals. It uses the Hall effect current mode as magnetoresistor but the output is the differential current instead of resistance. It shows good linearity and can detect the magnetic field direction. The sensitivity in the differential current of width 100 μm and length 200 μm at 1 mA is 2.788×10-6 A/T constantly while the conventional one in the differential resistance is varied with magnetic field. It is made of silicon non magnetic material so it is compatible with the modern low-voltage current-mode integrated circuit. © (2013) Trans Tech Publications, Switzerland.
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The deflection length and emitter width on sensitivity of magnetotransistor
(2011-10-04)
Phetchakul, Toempong
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Sottip, Panyakorn
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Leepattarapongpan, Chana
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Penpondee, Narichapan
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Pengpad, Putapon
This paper presents a study of effect of deflection length and emitter width on sensitivity of magnetotransistor. The device has been fabrication on standard CMOS technology. It can detect magnetic field applied vertically to the chip. The structure consists of emitter (n-type), base (p-type) and collector (n-type) on silicon p-substrate. The device can sense magnetic field by Hall Effect theory and carrier deflection resulting to difference between base and collector current (ΔI<inf>CB</inf>) related to magnetic field (B <inf>Z</inf>) strength. From the experiment is comparing emitter width of 4, 5 and 10 micrometer at deflection length of 10 and 20 micrometer. The result shows that increase in injection emitter width cause to the sensitivity decreases and the deflection length of 20 micrometer is the best sensitivity. These results are very useful for developing the magnetotransistor for high sensitivity and performance. © 2011 IEEE.
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Dual magnetodiode
(2009-12-01)
Phetchakul, Toempong
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Junkamkaw, Sumet
This paper presents magnetodiode which the structure consists of two pn junction diodes. The anodes are common together and the cathodes are symmetrical separated. It is designed, fabricated and measured the magnetic responses. The mechanism is mainly carrier deflection of injected carrier from the common anode by forward biasing toward to the separated cathode. When magnetic field is applied perpendicular to the device surface, the current difference caused by Hall effect and Lorentz force is linearly changed with the magnetic field density at any applied current. It can detect both the direction and magnitude of magnetic field.

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