Browsing by Author "Tsai, Shang-Wei"

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A Parylene-C based 16 Channels Flexible Bio-electrode for ECoG Recording
(2014)
Chou, Lei-Chun
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Tsai, Shang-Wei
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Chang, Wun-Lun
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Chiou, Jin-Chern
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Chiu, Tzai-Wen
Micro Electro Mechanical System (MEMS) technology is used in a bio-electrode for measuring electrocorticography (ECoG) signals in Sprague Dawley (SD) rats. The electrical signal in the rat brain is evoked by auditory stimulation and can be detected with newly developed bio-electrode sensors. A back-end system can record signals from eighteen positions. One signal was used as the ground signal, and one was used as the reference signal. The average results for 100 samples revealed the relationship between temporal resolution and spatial resolution of sixteen positions in the brain. The bioelectrode was fabricated with two parylene layers (10um, 1um) to cover the platinum metal wires. Oxygen plasma is used to etch the bioelectrode and to define a stable size and shape in production of batches of electrodes. To simplify implantation, the bioelectrode was designed to fit the curvature of SD rat head bones, and a special connector was used to transmit signals to the back-end system, which successfully recorded Auditory Evoked Potentials (AEP) signals after implant surgery.
Cooling Stimulation on Cerebral Cortex for Epilepsy Suppression with Integration of Micro-Invasive Electrodes and TE Coolers
(2013)
Chiou, Jin-Chern
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Chou, Lei-Chun
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Tsai, Shang-Wei
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Hou, Kuan-Chou
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Chang, Chih-Wei
Epilepsy suppression with cooling stimulation is the primary purpose for this study. In this dissertation, cooling stimulation was implemented and demonstrated on cerebral cortex of rats. Electrodes with needle structure was designed and fabricated by using MEMS technology to minimize the size of device. A TE cooler was used to create cooling source and it can be control via electrical current. A cooler component was integrated with an electrode and a TE cooler, in addition, a thermal sensor was also combined with it to detect temperature variation, which was affected by cooling cerebral cortex. The cooler components were implanted on surface of cerebral with deep brain stimulation and the thermal sensors were penetrated into cortex to measure temperature variation which can verify the functions of cooler components. In our experimental results, electrodes with needle structure can improve efficiency of epilepsy suppression due to the particular structure. Duration, frequency and average single time of epileptic waveforms were used to identify to performance of suppression.
Design and Fabricate a Contact Lens Sensor with a Micro-Inductor Embedded for Intraocular Pressure Monitoring
(2012)
Tseng, Chien-Kai
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Huang, Yu-Chieh
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Tsai, Shang-Wei
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Yeh, Guan-Ting
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Chang, Chung-Hao
This paper presents a new type of micro-inductor sensor for intraocular pressure (IOP) measurement on soft contact lens substructure. The sensor was designed and fabricated by using MEMS fabrication technologies. The contact lens is for wearing on a cornea such that a curvature of the contact lens corresponds substantially to that of the cornea, and is preferably made of Hydroxyethylmethacrylate (HEMA) by cast-molding method of soft contact lens for high oxygen permeability and comfortable long-duration wearing. In this paper, we discuss a contact lens with micro-inductor measurement principle followed by a brief description of our sensor design and fabrication. Our first prototype without wireless has been tested in lab-simulation bench. We obtain a simulation and measurement results have good linearity between micro-inductor radius variation and oscillation frequency. In future work will be to optimize the fabrication technology and the design to reach a better resolution, also a radio frequency integrated circuit (RFIC) and antenna will be designed preferably embedded in the contact lens so that inductance value transfers to frequency value via LC oscillator circuit and transmits intraocular pressure sensing signal by wireless telemetry system.
Design and Fabrication of Micromachined LPD-based SnO2 Gas Sensor Integrated TaN with Micro-hotplate
(2012)
Chiou, Jin-Chern
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Lin, Chia-Yang
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Tsai, Shang-Wei
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Hong, Wei-Che
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Chiou, Jin-Chern
In this study, the design and fabrication of a micromachined LPD-based SnO2 gas sensor integrated with TaN micro-hotplate was carried out by utilizing MEMS technology. In the characteristics of the micro-heater, thermal response, thermal distribution and power consumption of heated TaN micro-heater were measured by FLIR systems. For the sensing characterization, the sensing responses of LPD-based SnO2 gas sensor with TaN micro-heater to H2S gas were measured in different operating temperatures. In sensing properties, the resistances of the gas sensor significantly change in the staircase concentration of H2S gas and which optimal operating temperature was 250 degrees C.
Development of Micro-hotplate with TaN Heater Based Cu-doped SnO2 Gas Sensor for Low Concentration of H2S Gas
(2013)
Chiou, Jin-Chern
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Tsai, Shang-Wei
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Lin, Chia-Yang
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Chiou, Jin-Chern
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電機學院
In this study, the MEMS-based SnO2 gas sensor with a TaN heater, MSGST, was designed and fabricated using micromachining technology. The heating performance of the TaN heater was measured using an IR thermometer. The response of the MSGST sensor to H2S gas was analyzed by obtaining the relationship between the resistance of the sensor and the gas concentration to determine the best design parameters. Experimental results indicate that a MEMS-based SnO2 gas sensor, integrating TaN with a micro-hotplate, was successfully implemented using micromachining technology. The TaN heater can operate at over 300 degrees C and produce a uniform thermal distribution on the micro-hotplate. The sensitivity of the MSGST sensor to the H2S gas is significantly improved using a Cu catalyst and the optimal design parameters (Sensing film = 100 mu m(2), Cu catalyst = 7.5 mM) are obtained by measuring the gas concentration characterization for each the designed sensor.
Effect of SiO(2) Additive As Inhibitor on Crystalline Structure and H(2)S Sensing Performance of CuO-Au-SnO(2) Thin Film Prepared by Liquid Phase Deposition
(2010-01-01)
Chiou, Jin-Chern
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Tsai, Shang-Wei
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Chiou, Jin-Chern
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Huang, Cheng-Tang
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電機工程學系
In situ SiO(2)-doped SnO(2) thin films have been prepared by liquid phase deposition method. The effect of SiO(2) additive on the surface morphology and crystalline structural of the thin films were investigated by grazing incident angle X-ray diffraction (GIAXRD) and scanning electron microscopy (SEM). In the characteristics of sensing response, the SiO(2)-doped CuO-Au-SnO(2) gas sensors (Si/Sn = 0.25 and 0.33) have greater sensitivity and shorter response time than CuO-Au-SnO(2) gas sensor. However, the doped CuO-Au-SnO(2) gas sensors (Si/Sn = 0.33) can obtained better sensitivity ( S = 67 for 2ppm) and response time (t90% < 3 s).
Effect of SiO2 Additive As Inhibitor on Crystalline Structure and H2S Sensing Performance of CuO-Au-SnO2 Thin Film Prepared by Liquid Phase Deposition
(2010-01-01)
Chiou, Jin-Chern
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Tsai, Shang-Wei
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Chiou, Jin-Chern
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Huang, Cheng-Tang
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電子工程學系及電子研究所
In situ SiO2-doped SnO2 thin films have been prepared by liquid phase deposition method. The effect of SiO2 additive on the surface morphology and crystalline structural of the thin films were investigated by grazing incident angle X-ray diffraction (GIAXRD) and scanning electron microscopy (SEM). In the characteristics of sensing response, the SiO2-doped CuO-Au-SnO2 gas sensors (Si/Sn = 0.25 and 0.33) have greater sensitivity and shorter response time than CuO-Au-SnO2 gas sensor. However, the doped CuO-Au-SnO2 gas sensors (Si/Sn = 0.33) can obtained better sensitivity ( S = 67 for 2ppm) and response time (t90% < 3 s).
Improved crystalline structure and H(2)S sensing performance of CuO-Au-SnO(2) thin film using SiO(2) additive concentration
(2011-03-01)
Tsai, Shang-Wei
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Chiou, Jin-Chern
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電機工程學系
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Department of Electrical and Computer Engineering
In situ SiO(2)-doped SnO(2) thin films were successfully prepared by liquid phase deposition. The influence of SiO(2) additive as an inhibitor on the surface morphology and the grain size for the thin film has been investigated. These results show that the morphology of SnO(2) film changes significantly by increasing the concentration of H(2)SiF(6) solution which decreases the grain size of SnO(2). The stoichiometric analysis of Si content in the SnO(2) film prepared from various Si/Sn molar ratios has also been estimated. For the sensing performance of H(2)S gas, the SiO(2)-doped Cu-Au-SnO(2) sensor presents better sensitivity to H(2)S gas compared with Cu-Au-SnO(2) sensor due to the fact that the distribution of SiO(2) particles in grain boundaries of nano-crystallines SnO(2) inhibited the grain growth (<6 nm) and formed a porous film. By increasing the Si/Sn molar ratio, the SiO(2)-doped Cu-Au-SnO(2) gas sensors (Si/Sn=0.5) exhibit a good sensitivity (S=67), a short response time (t(90%)<3 s) and a good gas concentration characteristic (alpha=0.6074). Consequently, the improvement of the nano-crystalline structures and high sensitivity for sensing films can be achieved by introducing SiO(2) additive into the SnO(2) film prepared by LPD method. (C) 2010 Elsevier B.V. All rights reserved.
Improved crystalline structure and H2S sensing performance of CuO-Au-SnO2 thin film using SiO2 additive concentration
(2011-03-01)
Tsai, Shang-Wei
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Chiou, Jin-Chern
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In situ SiO2-doped SnO2 thin films were successfully prepared by liquid phase deposition. The influence of SiO2 additive as an inhibitor on the surface morphology and the grain size for the thin film has been investigated. These results show that the morphology of SnO2 film changes significantly by increasing the concentration of H2SiF6 solution which decreases the grain size of SnO2. The stoichiometric analysis of Si content in the SnO2 film prepared from various Si/Sn molar ratios has also been estimated. For the sensing performance of H2S gas, the SiO2-doped Cu-Au-SnO2 sensor presents better sensitivity to H2S gas compared with Cu-Au-SnO2 sensor due to the fact that the distribution of SiO2 particles in grain boundaries of nano-crystallines SnO2 inhibited the grain growth (<6 nm) and formed a porous film. By increasing the Si/Sn molar ratio, the SiO2-doped Cu-Au-SnO2 gas sensors (Si/Sn=0.5) exhibit a good sensitivity (S=67), a short response time (t(90%)<3 s) and a good gas concentration characteristic (alpha=0.6074). Consequently, the improvement of the nano-crystalline structures and high sensitivity for sensing films can be achieved by introducing SiO2 additive into the SnO2 film prepared by LPD method. (C) 2010 Elsevier B.V. All rights reserved.
Liquid Phase Deposition Based SnO2 Gas Sensor Integrated With TaN Heater on a Micro-Hotplate
(2013-06-01)
Chiou, Jin-Chern
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Tsai, Shang-Wei
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Lin, Chia-Yang
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電子工程學系及電子研究所
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電控工程研究所
A micromachined liquid-phase deposition (LPD)-based SnO2 gas sensor that is integrated with a tantalum nitride (TaN) microheater on micro-hotplate is designed and fabricated using microelectromechanical systems technology. TaN is available in many traditional complementary metal oxide semiconductor designs, unlike many other microheater materials. For the initial time, TaN is used in semiconductor metal oxide gas sensor as a heater. The thermal response, thermal distribution, and power consumption of the TaN microheater are measured using a thermal imaging camera. The operating temperature of TaN micro-hotplate can exceed 500 degrees C and they have a favorable thermal distribution within the sensing area. The temperature variation over the sensing area for a TaN microheater with a size of 300 x 300 mu m is similar to 4% at 500 degrees C. Its power consumption is successfully decreased by adopting a structure with ratio of edge length of the membrane to that of the microheater of 2.5. The sensing responses of the LPD-based SnO2 gas sensor with the TaN microheater to H2S gas are measured at various operating temperatures. The optimal operating temperature of the designed gas sensors is in the range 250 degrees C-300 degrees C. The designed sensing film with an area of 100 x 100 mu m has greater sensitivity to a staircase concentration of H2S gas than those with the other two areas (200 x 200 mu m and 300 x 300 mu m).
Novel Application of Ring-oscillator-based Sensor for 3D IC Temperature and IR Drop Monitoring
(2017-01-01)
Chiou, Jin-Chern
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Yang, Tzu-Sen
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Tsai, Shang-Wei
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電機工程學系
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Department of Electrical and Computer Engineering
This paper proposes a novel method to clearly differentiate the distinct problems of temperature and IR drop inside a chip. This method involves the placement of two same ring-oscillator-based sensors in specific areas. Simulation results show that as temperature increases, the digital counter output of the ring-oscillator-based sensor decreases. Alternatively, a decrease in the power supply decreases the digital output of the ring-oscillator-based sensor. Results also show that when the digital circuit speed was slow, the difference between the digital count outputs of the two sensors became very small; this difference was very large when the speed was high. Thus, the difference between the digital count outputs of the two sensors represents the internal power status of the chip.
Toward A Wireless Contact Lens Sensor System with a Micro-Capacitor for Intraocular Pressure Monitoring on in-vitro Porcine Eye
(2015)
Yeh, Guan-Ting
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Wu, Tsung-Wei
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Tsai, Shang-Wei
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Hsu, Shun-Hsi
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Chiou, Jin-Chern
This work presents a type of capacitive sensor for intraocular pressure (IOP) measurement on soft contact lens with Radio Frequency Identification (RFID) module. The flexible capacitive IOP sensor and Rx antenna was designed and fabricated using MEMS fabrication technologies that can be embedded on a soft contact lens. The IOP sensing unit is a sandwich structure composed of parylene C as the substrate and the insulating layer, gold as the top and bottom electrodes of the capacitor, and Hydroxyethylmethacrylate (HEMA) as dielectric material between top plate and bottom plate. The main sensing principle is using wireless IOP contact lenses sensor (CLS) system placed on corneal to detect the corneal deformation caused due to the variations of IOP. The variations of intraocular pressure will be transformed into capacitance change and this change will be transmitted to RFID system and recorded as continuous IOP monitoring. The measurement on in-vitro porcine eyes show the pressure reproducibility and a sensitivity of 0.02 pF/4.5 mmHg