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Effect of amino-, mercapto-silane coupling as a molecular bridge of polyvinyl chloride ion-selective membrane on silicon nitride for nitrate ISFET sensors
(2020-06-01)
Chaisriratanakul, Woraphan
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Bunjongpru, Win
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Pankiew, Apirak
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Srisuwan, Awirut
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Jeamsaksiri, Wutthinan
This paper presents a modification of a Si<inf>3</inf>N<inf>4</inf> Polyvinyl chloride (PVC) membrane on a surface of an ion selective field effect transistor (ISFET) using silane with two different functional groups for comparison of nitrate sensing characteristics. Effects of amino (NH<inf>2</inf>) and thiol groups (SH) toward structures and characteristics of nitrate sensors were analyzed using the following techniques: ellipsometry, scanning electron microscope (SEM), infrared spectroscopy (FTIR), zeta potential and electrochemical impedance spectroscopy (EIS). After surface modification, the thickness of the silane layers for both cases were similar with uniform surface topology. Absolute zeta potentials of PVC ion-selective membrane (7.65 mV) and Si<inf>3</inf>N<inf>4</inf> surface modification with MPTMS (-51.46 mV) reflected the surface functional group and showed that membranes could be bonded to the PVC ion-selective membrane. Since APTMS produced higher EIS than MPTMS, the resulting nitrate sensors modified by MPTMS had higher sensitivity than the sensors with APTMS. Finally, the modified sensors had a useful life time of 3 months.
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Modification of polyvinyl chloride ion-selective membrane for nitrate ISFET sensors
(2020-05-15)
Chaisrirattanakua, Woraphan
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Bunjongpru, Win
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Pankiew, Apirak
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Srisuwan, Awirut
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Jeamsaksiri, Wutthinan
In this work, a Polyvinyl Chloride (PVC) ion-selective membrane was modified to detect nitrate based on Ion Selective Field Effect Transistor (ISFET) sensing technology in order to eliminate chloride interference. A modification was done with ethylenediamine solution to achieve animated PVC, which was then oxidized with sodium tungstate to form nitrone coated PVC membrane. The modified PVC was characterized using FTIR, 1H NMR, GPC, FE-SEM and EIS. The FTIR spectrum of animate PVC demonstrated -NH<inf>2</inf> bending at 1580 cm−1, NO<inf>2</inf> asymmetric stretching at 1650 cm−1 and N[sbnd]O out-of-plane deformation vibration at 837 cm−1. GPC analysis of the modified PVC showed that the PVC molecular weight was shifted to a high molecular weight. The PVC ion-selective membrane was immobilized on the ISFET to create nitrate sensors with the following characteristics. The Nitrate-Nitrogen detection limit is 1.20 ppm with linear range from 3−20 ppm at sensitivity of 56 ± 2 mV/dec. The sensor is useful for detecting small amount of nitrate in a mixed solution, which usually is the case in most situations. This sensor could be applied in many applications, such as agricultural industry, water reserve management and medical field as well.
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Effects of Annealing Process on the Electrical Properties of MEMS Capacitive Microphone
(2018-07-02)
Jantawong, Jirawat
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Leepattarapongpan, Chana
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Chaowicharat, Ekalak
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Jeamsaksiri, Wutthinan
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Austin, Anu
In this paper, the effects of annealing temperature after pre-bonding device wafer and cover wafer during wafer fusion bonding process on the electrical properties of MEMS-based capacitive microphone with 0.53 μm thick poly-Si membrane were investigated. By the annealing in N2 ambient (14 SLM) at 900°C for 30 min, the device exhibited capacitance of 2.0 pF with pull-in voltage of 12 V. The significantly improvement of electrical properties is related to the reducing of residual stress in poly-Si membrane to near-zero level by using suitable annealing condition.
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The magnetotransistor for 2-axis magnetic field measurement in CMOS technology
(2015-08-17)
Leepattarapongpan, Chana
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Phetchakul, Toempong
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Pengpad, Puttapon
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Srihapat, Arckom
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Jeamsaksiri, Wutthinan
This paper presents a magnetotransistor for detecting magnetic field in vertical and lateral directions (B<inf>Y</inf> and B<inf>Z</inf>) by relying on the difference between base and collector currents (ΔI<inf>CB</inf>). It was designed and fabricated using CMOS fabrication technology. The device structure consisted of one emitter, 4 collectors and 4 bases. The experiment showed that, at 10 mA of biasing current, the B<inf>Y</inf> and B<inf>Z</inf> direction sensitivity to magnetic field within the range of 0 - 400 mT are 0.7 and 1.35 %/T, respectively. The sensitivity at emitter current 20mA are 0.55 and 0.7 %/T for vertical and lateral magnetic field directions, respectively. This research on the magnetotransistor produced magnetic sensors with small size, high performance with wide range of applications.
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The increase sensitivity of PNP-magnetotransistor in CMOS technology
(2015-02-02)
Leepattarapongpan, Chana
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Phetchakul, Toempong
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Pengpad, Puttapon
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Srihapat, Arckom
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Jeamsaksiri, Wutthinan
This paper presents improve sensitivity of pnp-magnetotransistor for detect vertical magnetic field response. The device structure consisted of one emitter, four collectors and four bases. The four collectors are separate to form four terminals. The same is true for the four bases. The experiment showed that, at 2 and 4mA of biasing current, magnetic field in B<inf>Z</inf> direction sensitivity within the range of 0-400 mT are 0.045 and 0.09 mV/mT in single mode. The sensitivity of merge mode are 0.15 and 0.3 mV/mT. The magnetic field response of merge mode shows 4-time increase of the magnetic field sensitivity comparative to single mode.
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A merged magnetotransistor for 3-axis magnetic field measurement based on carrier recombination-deflection effect
(2014-01-01)
Leepattarapongpan, Chana
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Phetchakul, Toempong
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Penpondee, Naritchaphan
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Pengpad, Puttapon
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Srihapat, Arckom
This article presents a novel magnetotransistor based on carrier recombination-deflection effect for detecting magnetic field in three dimensions (B<inf>X</inf>, B<inf>Y</inf>, and B<inf>Z</inf>) by relying on the difference between base and collector currents (I<inf>CB</inf>). This device used low biasing current. It was designed and fabricated using CMOS fabrication technology. The device structure consisted of one emitter, 4 collectors and 4 bases. All four collector terminals were connected with each other. The same was true for the four base terminals. LOCOS oxide was grown to surround the emitter area to limit lateral carrier loss, and therefore reducing the overall biasing current. The experiment showed that, at 0.2 mA of biasing current, the B <inf>X</inf>, B<inf>Y</inf> and B<inf>-Z</inf> direction sensitivity to magnetic field within the range of 0-400 mT are 2, 5 and 14.5%/T, respectively. This research on the merged magnetotransistor produced magnetic sensors with small size, high performance with wide range of applications. © 2014 Elsevier Ltd.
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An improvement of the breakdown voltage characteristics of NPT-TIGBT by using a P-buried layer
(2013-08-30)
Manosukritkul, Phasapon
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Kerdpardist, Amonrat
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Saenlamool, Montree
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Chaowicharat, Ekalak
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Poyai, Amporn
In this paper, we introduced a P-buried (P<inf>b</inf>) layer under trench gate which relieved the electric field crowding in the Non Punch Through Trench gate Insulated Gate Bipolar Transistor (NPT-TIGBT) structure. The P<inf>b</inf> layer, with carrier concentration of 5 ×1016 cm-3, was created underneath the trench gate within the n-drift layer. In this way, the concentration of electric field at the trench bottom corner decreased. As a result, the breakdown voltage characteristics of NPT-TIGBT improved. The structures were proposed and verified by T-CAD Sentuarus simulation. From the simulation results, the breakdown voltage increased by approximately 30% compared with conventional NPT-TIGBT. © (2013) Trans Tech Publications, Switzerland.
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The study of p-n and schottky junction for magnetodiode
(2012-01-01)
Phetchakul, Toempong
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Luanatikomkul, Wittaya
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Leepattarapongpan, Chana
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Chaowicharat, Ekalak
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Pengpad, Putapon
This paper presents the simulation model of Dual Magnetodiode and Dual Schottky Magnetodiode using Sentaurus TCAD to simulate the virtual structure of magneto device and apply Hall Effect to measure magnetic field response of the device. Firstly, we use the program to simulate the magnetodiode with p-type semiconductor and aluminum anode and measure electrical properties and magnetic field sensitivity. Simulation results show that sensitivity of Dual Schottky magnetodiode is higher than that of Dual magnetodiode.
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The low power 3D-magnetotransistor based on CMOS technology
(2011-12-01)
Leepattarapongpan, Chana
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Phetchakul, Toempong
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Penpondee, Naritchaphan
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Pengpad, Puttapon
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Srihapat, Arckom
This article presents a 3D magnetotransistor for detecting magnetic field in three dimensions (B <inf>X</inf>, B <inf>Y</inf>, and B <inf>Z</inf>) by relying on the difference between base and collector currents (ΔI <inf>CB</inf>). This device used low biasing current. It was designed and fabricated using CMOS fabrication technology. The device structure consisted of one emitter, 4 collectors and 4 bases. LOCOS oxide was grown to surround the emitter area to limit lateral carrier loss, and therefore reducing the overall biasing current. The experiment showed that, at 0.2 mA of biasing current, the BX, BY and BZ direction sensitivity to magnetic field within the range of 0 - 400 mT are 0.05, 0.07 and 0.145 mV/mT, respectively. © 2011 IEEE.

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