13 results on '"Liang Dai"'
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2. Manufacturing and Characterization of a Thermoelectric Energy Harvester Using the CMOS-MEMS Technology.
- Author
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Shih-Wen Peng, Po-Jen Shih, and Ching-Liang Dai
- Published
- 2015
- Full Text
- View/download PDF
3. Thermoelectric Energy Micro Harvesters with Temperature Sensors Manufactured Utilizing the CMOS-MEMS Technique
- Author
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Yi-Xuan Shen, Yao-Chuan Tsai, Chi-Yuan Lee, Chyan-Chyi Wu, and Ching-Liang Dai
- Subjects
thermoelectric energy micro harvester ,complementary metal oxide semiconductor ,microelectromechanical system ,thermocouple ,cooling sheet ,Control and Systems Engineering ,Mechanical Engineering ,Electrical and Electronic Engineering - Abstract
This study develops a TEMH (thermoelectric energy micro harvester) chip utilizing a commercial 0.18 μm CMOS (complementary metal oxide semiconductor) process. The chip contains a TEMH and temperature sensors. The TEMH is established using a series of 54 thermocouples. The use of the temperature sensors monitors the temperature of the thermocouples. One temperature sensor is set near the cold part of the thermocouples, and the other is set near the hot part of the thermocouples. The performance of the TEMH relies on the TD (temperature difference) at the CHP (cold and hot parts) of the thermocouples. The more the TD at the CHP of the thermocouples increases, the higher the output voltage and output power of the TEMH become. To obtain a higher TD, the cold part of the thermocouples is designed as a suspended structure and is combined with cooling sheets to increase heat dissipation. The cooling sheet is constructed of a stack of aluminum layers and is mounted above the cold part of the thermocouple. A finite element method software, ANSYS, is utilized to compute the temperature distribution of the TEMH. The TEMH requires a post-process to obtain the suspended thermocouple structure. The post-process utilizes an RIE (reactive ion etch) to etch the two sacrificial materials, which are silicon dioxide and silicon substrate. The results reveal that the structure of the thermocouples is completely suspended and does not show any injury. The measured results reveal that the output voltage of the TEMH is 32.5 mV when the TD between the CHP of the thermocouples is 4 K. The TEMH has a voltage factor of 8.93 mV/mm2K. When the TD between the CHP of the thermocouples is 4 K, the maximum output power of the TEMH is 4.67 nW. The TEMH has a power factor of 0.31 nW/mm2K2.
- Published
- 2022
4. Laser-Induced Graphene Stretchable Strain Sensor with Vertical and Parallel Patterns
- Author
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Yu-Hsin Yen, Chao-Shin Hsu, Zheng-Yan Lei, Hsin-Jou Wang, Ching-Yuan Su, Ching-Liang Dai, and Yao-Chuan Tsai
- Subjects
laser-induced graphene ,stretchable strain sensor ,gauge factor ,polymer carbonization ,Control and Systems Engineering ,Mechanical Engineering ,Electrical and Electronic Engineering - Abstract
In intelligent manufacturing and robotic technology, various sensors must be integrated with equipment. In addition to traditional sensors, stretchable sensors are particularly attractive for applications in robotics and wearable devices. In this study, a piezoresistive stretchable strain sensor based on laser-induced graphene (LIG) was proposed and developed. A three-dimensional, porous LIG structure fabricated from polyimide (PI) film using laser scanning was used as the sensing layer of the strain sensor. Two LIG pattern structures (parallel and vertical) were fabricated and integrated within the LIG strain sensors. Scanning electron microscopy, an X-ray energy dispersive spectrometer, and Raman scattering spectroscopy were used to examine the microstructure of the LIG sensing layer. The performance and strain sensing properties of the parallel and vertical stretchable LIG strain sensors were investigated in tensile tests. The relative resistance changes and the gauge factors of the parallel and vertical LIG strain sensors were quantified. The parallel strain sensor achieved a high gauge factor of 15.79 in the applied strain range of 10% to 20%. It also had high sensitivity, excellent repeatability, good durability, and fast response times during the tensile experiments. The developed LIG strain sensor can be used for the real-time monitoring of human motions such like finger bending, wrist bending, and throat swallowing.
- Published
- 2022
5. Design and Measurement of Microelectromechanical Three-Axis Magnetic Field Sensors Based on the CMOS Technique
- Author
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Chi-Han Wu, Cheng-Chih Hsu, Yao-Chuan Tsai, Chi-Yuan Lee, and Ching-Liang Dai
- Subjects
three-axis magnetic field sensor ,cross-sensitivity ,sensitivity ,MEMS ,CMOS ,Control and Systems Engineering ,Mechanical Engineering ,Electrical and Electronic Engineering - Abstract
The design, fabrication, and measurement of a microelectromechanical system (MEMS) three-axis magnetic field sensor (MFS) based on the commercial complementary metal oxide semiconductor (CMOS) process are investigated. The MFS is a magnetic transistor type. The performance of the MFS was analyzed employing the semiconductor simulation software, Sentaurus TCAD. In order to decrease the cross-sensitivity of the three-axis MFS, the structure of the MFS is planed to accommodate two independent sensing components, a z-MFS utilized to sense magnetic field (M-F) in the z-direction and a y/x-MFS composed of a y-MFS and a x-MFS to be utilized to sense M-F in the y- and x-directions. The z-MFS incorporates four additional collectors to increase its sensitivity. The commercial 1P6M 0.18 μm CMOS process of the Taiwan Semiconductor Manufacturing Company (TSMC) is utilized to manufacture the MFS. Experiments depict that the MFS has a low cross-sensitivity of less than 3%. The sensitivities of z-, y-, and x-MFS are 237 mV/T, 485 mV/T, and 484 mV/T, respectively.
- Published
- 2023
6. Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS-MEMS Technique
- Author
-
Yao-Chuan Tsai, Ching-Liang Dai, Po-Jen Shih, Wei-Chun Shen, and Cheng-Chih Hsu
- Subjects
CMOS process ,Materials science ,Fabrication ,Silicon ,Scanning electron microscope ,lcsh:Mechanical engineering and machinery ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,01 natural sciences ,ammonia ,Article ,law.invention ,gas sensor ,chemistry.chemical_compound ,law ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,Microelectromechanical systems ,Graphene ,business.industry ,Mechanical Engineering ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,low concentration ,MEMS ,chemistry ,CMOS ,Control and Systems Engineering ,Optoelectronics ,0210 nano-technology ,business - Abstract
This study describes the fabrication of an ammonia gas sensor (AGS) using a complementary metal oxide semiconductor (CMOS)&ndash, microelectromechanical system (MEMS) technique. The structure of the AGS features interdigitated electrodes (IDEs) and a sensing material on a silicon substrate. The IDEs are the stacked aluminum layers that are made using the CMOS process. The sensing material, polypyrrole/reduced graphene oxide (PPy/RGO), is synthesized using the oxidation&ndash, reduction method, and the material is characterized using an electron spectroscope for chemical analysis (ESCA), a scanning electron microscope (SEM), and high-resolution X-ray diffraction (XRD). After the CMOS process, the AGS needs post-processing to etch an oxide layer and to deposit the sensing material. The resistance of the AGS changes when it is exposed to ammonia. A non-inverting amplifier circuit converts the resistance of the AGS into a voltage signal. The AGS operates at room temperature. Experiments show that the AGS response is 4.5% at a concentration of 1 ppm NH3, and it exhibits good repeatability. The lowest concentration that the AGS can detect is 0.1 ppm NH3
- Published
- 2019
7. Fabrication and Characterization of Flexible Thermoelectric Generators Using Micromachining and Electroplating Techniques
- Author
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Ching-Liang Dai, Wnag-Lin Lee, Po-Jen Shih, and Cheng-Chih Hsu
- Subjects
Materials science ,Fabrication ,lcsh:Mechanical engineering and machinery ,electroplating ,thermoelectric generator ,02 engineering and technology ,Substrate (electronics) ,01 natural sciences ,Article ,Thermocouple ,0103 physical sciences ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,Composite material ,micromachining ,Electroplating ,010302 applied physics ,Mechanical Engineering ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,thermocouple ,Surface micromachining ,flexibility ,Thermoelectric generator ,Control and Systems Engineering ,0210 nano-technology ,Layer (electronics) - Abstract
This study involves the fabrication and measurement of a flexible thermoelectric generator (FTG) using micromachining and electroplating processes. The area of the FTG is 46 ×, 17 mm2, and it is composed of 39 thermocouples in series. The thermoelectric materials that are used for the FTG are copper and nickel. The fabrication process involves patterning a silver seed layer on the polymethyl methacrylate (PMMA) substrate using a computer numerical control (CNC) micro-milling machine. Thermoelectric materials, copper and nickel, are deposited on the PMMA substrate using an electroplating process. An epoxy polymer is then coated onto the PMMA substrate. Acetone solution is then used to etch the PMMA substrate and to transfer the thermocouples to the flexible epoxy film. The FTG generates an output voltage (OV) as the thermocouples have a temperature difference (&Delta, T) between the cold and hot parts. The experiments show that the OV of the FTG is 4.2 mV at &Delta, T of 5.3 K and the output power is 429 nW at &Delta, T of 5.3 K. The FTG has a voltage factor of 1 &mu, V/mm2K and a power factor of 19.5 pW/mm2K2. The FTG reaches a curvature of 20 m&minus, 1.
- Published
- 2019
- Full Text
- View/download PDF
8. Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology
- Author
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Ching-Liang Dai, Cheng Chih Hsu, and Cheng-Yang Lin
- Subjects
Materials science ,Fabrication ,business.industry ,lcsh:Mechanical engineering and machinery ,Mechanical Engineering ,Coplanar waveguide ,Electrical engineering ,radio frequency ,Inductor ,Finite element method ,Control and Systems Engineering ,micromachined switches ,CMOS-MEMS ,Insertion loss ,lcsh:TJ1-1570 ,Radio frequency ,Electrical and Electronic Engineering ,business ,Layer (electronics) ,Voltage - Abstract
The study investigates the design and fabrication of a micromachined radio frequency (RF) capacitive switch using the complementary metal oxide semiconductor-microelectromechanical system (CMOS-MEMS) technology. The structure of the micromachined switch is composed of a membrane, eight springs, four inductors, and coplanar waveguide (CPW) lines. In order to reduce the actuation voltage of the switch, the springs are designed as low stiffness. The finite element method (FEM) software CoventorWare is used to simulate the actuation voltage and displacement of the switch. The micromachined switch needs a post-CMOS process to release the springs and membrane. A wet etching is employed to etch the sacrificial silicon dioxide layer, and to release the membrane and springs of the switch. Experiments show that the pull-in voltage of the switch is 12 V. The switch has an insertion loss of 0.8 dB at 36 GHz and an isolation of 19 dB at 36 GHz.
- Published
- 2015
9. Manufacturing and Characterization of a Thermoelectric Energy Harvester Using the CMOS-MEMS Technology
- Author
-
Po-Jen Shih, Shih-Wen Peng, and Ching-Liang Dai
- Subjects
Microelectromechanical systems ,Engineering ,Silicon ,business.industry ,lcsh:Mechanical engineering and machinery ,Mechanical Engineering ,CMOS ,Mechanical engineering ,chemistry.chemical_element ,Power factor ,thermoelectric ,energy harvester ,MEMS ,chemistry ,Control and Systems Engineering ,Thermocouple ,Thermoelectric effect ,Optoelectronics ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,business ,Energy harvesting ,Voltage - Abstract
The fabrication and characterization of a thermoelectric energy harvester using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technology were presented. The thermoelectric energy harvester is composed of eight circular energy harvesting cells, and each cell consists of 25 thermocouples in series. The thermocouples are made of p-type and n-type polysilicons. The output power of the energy harvester relies on the number of the thermocouples. In order to enhance the output power, the energy harvester increases the thermocouple number per area. The energy harvester requires a post-CMOS process to etch the sacrificial silicon dioxide layer and the silicon substrate to release the suspended structures of hot part. The experimental results show that the energy harvester has an output voltage per area of 0.178 mV·mm−2·K−1 and a power factor of 1.47 × 10−3 pW·mm−2·K−2.
- Published
- 2015
10. Micro Magnetic Field Sensors Manufactured Using a Standard 0.18-μm CMOS Process
- Author
-
Yen-Nan Lin and Ching-Liang Dai
- Subjects
Materials science ,Fabrication ,lcsh:Mechanical engineering and machinery ,magnetic field ,02 engineering and technology ,01 natural sciences ,Article ,magnetotransistor ,micro sensor ,Hall effect ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,Common emitter ,business.industry ,Mechanical Engineering ,010401 analytical chemistry ,Biasing ,Sense (electronics) ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Magnetic field ,CMOS ,Control and Systems Engineering ,Optoelectronics ,0210 nano-technology ,business ,Sensitivity (electronics) - Abstract
Micro magnetic field (MMF) sensors developed employing complementary metal oxide semiconductor (CMOS) technology are investigated. The MMF sensors, which are a three-axis sensing type, include a magnetotransistor and four Hall elements. The magnetotransistor is utilized to detect the magnetic field (MF) in the x-axis and y-axis, and four Hall elements are used to sense MF in the z-axis. In addition to emitter, bases and collectors, additional collectors are added to the magnetotransistor. The additional collectors enhance bias current and carrier number, so that the sensor sensitivity is enlarged. The MMF sensor fabrication is easy because it does not require post-CMOS processing. Experiments depict that the MMF sensor sensitivity is 0.69 V/T in the x-axis MF and its sensitivity is 0.55 V/T in the y-axis MF.
- Published
- 2018
11. Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology.
- Author
-
Cheng-Yang Lin, Cheng-Chih Hsu, and Ching-Liang Dai
- Subjects
RADIO frequency ,FINITE element method ,COMPLEMENTARY metal oxide semiconductors - Abstract
The study investigates the design and fabrication of amicromachined radio frequency (RF) capacitive switch using the complementary metal oxide semiconductor-microelectromechanical system (CMOS-MEMS) technology. The structure of the micromachined switch is composed of a membrane, eight springs, four inductors, and coplanar waveguide (CPW) lines. In order to reduce the actuation voltage of the switch, the springs are designed as low stiffness. The finite element method (FEM) software CoventorWare is used to simulate the actuation voltage and displacement of the switch. The micromachined switch needs a post-CMOS process to release the springs and membrane. A wet etching is employed to etch the sacrificial silicon dioxide layer, and to release the membrane and springs of the switch. Experiments show that the pull-in voltage of the switch is 12 V. The switch has an insertion loss of 0.8 dB at 36 GHz and an isolation of 19 dB at 36 GHz. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
12. Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS–MEMS Technique
- Author
-
Wei-Chun Shen, Po-Jen Shih, Yao-Chuan Tsai, Cheng-Chih Hsu, and Ching-Liang Dai
- Subjects
ammonia ,gas sensor ,low concentration ,cmos process ,mems ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
This study describes the fabrication of an ammonia gas sensor (AGS) using a complementary metal oxide semiconductor (CMOS)−microelectromechanical system (MEMS) technique. The structure of the AGS features interdigitated electrodes (IDEs) and a sensing material on a silicon substrate. The IDEs are the stacked aluminum layers that are made using the CMOS process. The sensing material; polypyrrole/reduced graphene oxide (PPy/RGO), is synthesized using the oxidation−reduction method; and the material is characterized using an electron spectroscope for chemical analysis (ESCA), a scanning electron microscope (SEM), and high-resolution X-ray diffraction (XRD). After the CMOS process; the AGS needs post-processing to etch an oxide layer and to deposit the sensing material. The resistance of the AGS changes when it is exposed to ammonia. A non-inverting amplifier circuit converts the resistance of the AGS into a voltage signal. The AGS operates at room temperature. Experiments show that the AGS response is 4.5% at a concentration of 1 ppm NH3; and it exhibits good repeatability. The lowest concentration that the AGS can detect is 0.1 ppm NH3
- Published
- 2020
- Full Text
- View/download PDF
13. Fabrication and Characterization of Flexible Thermoelectric Generators Using Micromachining and Electroplating Techniques
- Author
-
Wnag-Lin Lee, Po-Jen Shih, Cheng-Chih Hsu, and Ching-Liang Dai
- Subjects
thermoelectric generator ,flexibility ,micromachining ,electroplating ,thermocouple ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
This study involves the fabrication and measurement of a flexible thermoelectric generator (FTG) using micromachining and electroplating processes. The area of the FTG is 46 × 17 mm2, and it is composed of 39 thermocouples in series. The thermoelectric materials that are used for the FTG are copper and nickel. The fabrication process involves patterning a silver seed layer on the polymethyl methacrylate (PMMA) substrate using a computer numerical control (CNC) micro-milling machine. Thermoelectric materials, copper and nickel, are deposited on the PMMA substrate using an electroplating process. An epoxy polymer is then coated onto the PMMA substrate. Acetone solution is then used to etch the PMMA substrate and to transfer the thermocouples to the flexible epoxy film. The FTG generates an output voltage (OV) as the thermocouples have a temperature difference (ΔT) between the cold and hot parts. The experiments show that the OV of the FTG is 4.2 mV at ΔT of 5.3 K and the output power is 429 nW at ΔT of 5.3 K. The FTG has a voltage factor of 1 μV/mm2K and a power factor of 19.5 pW/mm2K2. The FTG reaches a curvature of 20 m−1.
- Published
- 2019
- Full Text
- View/download PDF
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