Browsing by Author "Chang, Kow-Ming"

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A novel design of a CPW-fed single square-loop antenna for circular polarization
(2008-09-01)
Deng, I-Chung
;
Lin, Ren-Jie
;
Ke, Qing-Xiang
;
Huang, Jia-Min
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Chang, Kow-Ming
The experimental and simulated results for the proposed antenna are investigated in this article. Moreover, a novel broadband design of a circularly polarized (CP) single square slot antenna fed by a single coplanar waveguide is presented. By appropriately choosing the circumference of the square-loop, the length of the protruded strip, and the gap, this proposed antenna thus owns good CP radiation and good impedance match simultaneously at the frequency of 2.45 GHz. This proposed antenna has the fundamental resonant frequency of 2.5 GHz with the minimum return loss of -39.9 dB. Furthermore, its impedance bandwidth is 460 MHz or 18.4% and 3-dB axial-ratio (AR) bandwidth is 360 MHz or 14.4% at 2.5 GHz.
A novel design of a CPW-fed square slot antenna with broadband circular polarization
(2006-12-01)
Chang, Kow-Ming
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Lin, Ren-Jie
;
Deng, I-Chung
;
Chen, Jin-Bo
;
Xiang, Ke Qing
A novel design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide is proposed and discussed. The circularly polarized radiation is achieved by means of using an outer rectangular ring and an inner rectangular ring at the center of a square slot. The proposed antenna has the fundamental resonant frequency of 2.44 GHz with the return loss of -40.93 dB, and it has the bandwidth of 3 dB axial ratio of 420 MHz or (17.21%). Details of the results are presented and discussed. (c) 2006 Wiley Periodicals, Inc.
A novel design of a microstrip-fed shorted square-ring slot antenna for circular polarization
(2007-07-01)
Chang, Kow-Ming
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Lin, Ren-Jie
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Deng, I-Chung
;
Ke, Qing-Xiang
;
電子工程學系及電子研究所
The design of a circularly polarized slot antenna fed by a single microstrip line is presented. The circularly polarized radiation is achieved by means of using a shorted square-ring slot. This proposed antenna has the fundamental resonant frequency of 2.4 GHz with the minimum return loss of -50.44 dB. The impedance bandwidth is 930 MHz or 38.7% referred to the resonant frequency, and it also has the 3-dB axial-ratio (AR) bandwidth of 310 MHz or 12.9% referred to the resonant frequency. In addition, this proposed antenna shows good performance of circular polarization (CP) radiation with the range of the lower 3-dB AR value covering elevation angles between -40 to 40 degrees. (C) 2007 Wiley Periodicals, Inc.
A Novel pH-dependent Drift Improvement Method for Zirconium Dioxide Gated pH-Ion Sensitive Field Effect Transistors
(2010-05-01)
Chang, Kow-Ming
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Chang, Chih-Tien
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Chao, Kuo-Yi
;
Lin, Chia-Hung
;
電子工程學系及電子研究所
A novel compensation method for Zirconium dioxide gated Ion Sensitive Field Effect Transistors (ISFETs) to improve pH-dependent drift was demonstrated. Through the sequential measurements for both the n-channel and p-channel ISFETs, 75-100% pH-dependent drift could be successfully suppressed for the first seven hours. As a result, a nearly constant drift rate versus pH value was obtained, which increases the accuracy of pH measurements. Meanwhile, the drawback of the hyperbolic-like change with time of the common drift behavior for ISFETs was improved. A state-of-the-art integrated scheme adopting this method was also illustrated.
A novel technique for measuring pico-scale flow rate of a liquid solution using a microchannel
(2008-03-28)
Chang, Kow-Ming
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Chao, Kuo-Yi
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Lin, Kun-Feng
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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
As micrototal analysis system (mu-TAS) becoming more extensively used, techniques for fabricating microchannels, microactuators, and measuring systems are becoming increasingly important. This study describes a novel method for fabricating a closed microchannel that can be used to measure the pico-scale flow rate of a liquid solution with an accuracy of better than 1 pL/s. The flow rate of 9 pL/s is calculated from the measurements. Without any high temperature or high-voltage processing, the microchannel can be integrated in the complementary metal-oxide-semiconductor (CMOS) microfluidic system and the fabricating process involves only some standard CMOS processes and common materials. The batch fabrication of a single integrated circuit (IC) chip is essential to reaching the goal of a system in one chip. (C) 2007 Elsevier B.V. All rights reserved.
ANNEALING TEMPERATURE EFFECT ON THE SENSITIVITY OF SIGE NANOWIRE FOR BIO-SENSOR
(2011)
Chang, Kow-Ming
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Chen, Chu-Feng
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Wang, Yu-Bin
;
Liu, Chung-Hsien
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Kuo, Jiun-Ming
Nanowire is widely used in biological sensor because it has the high surface-to-volume ratio. Germanium (Ge) would be beneficial to enhance the sensitivity of silicon nanowire for bio-sensor. In this study, we have successfully fabricated the SiGe on Insulator (SGOI) nanowires with different annealing temperature by side-wall spacer technique, respectively. The 3-amino-propyltrime-thoxy-silane (APTS) is used to modify the surface, which can connect the bio-linker. Nanowire is considered as a resistance, and the change of conductance (Delta G) and sensitivity (S) of different samples corresponding to APTS treatment were investigated. As annealing temperature was elevated from 800 to 950 degrees C, the SiGe nanowire exhibited increasing sensitivity in the chemical detection. However, it was noted that degradation of sensitivity was observed as the annealing temperature increases up to 1000 degrees C. This behavior may be associated with the reduction of the Ge concentration at the surface of SiGe nanowire due to high-temperature diffusion of Ge in Si. So, temperature is a key parameter in the annealing process producing two effects: repairs of defects and Ge diffusion. There would be an optimal annealing temperature between 900 and 1000 degrees C.
Bias Temperature Instabilities for High-kappa HfO2 LTPS-TFTs With Dual Plasma Treatment
(2016-03)
Wu, Chien-Hung
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Huang, Bo-Wen
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Chang, Kow-Ming
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Chang, Ting-Chia
;
Wang, Shui-Jinn
This study is the first to investigate different reliability mechanisms of high-performance low-temperature polycrystalline silicon thin-film transistors (TFTs) with a HfO2 gate dielectric before and after dual plasma treatment (DPT) under various bias temperature instability (BTI) stresses. DPT samples under positive bias temperature instability (PBI) and negative bias temperature instability (NBI) stresses exhibited different degradation phenomena because of the negative polarity trapped oxide charges and positive fixed oxide charges (Si+), respectively. In addition, experimental data exhibited better reliability immunity for PBI stress than NBI stress after DPT. Furthermore, we raised the temperature to clearly observe the effect of the PBTI stress analysis for samples with and without DPT. Extracted measurement results showed distinct time evolutions of the interface state densities (Nit) for samples with and without DPT, revealing the different mechanisms of Nit generation with and without DPT. Finally, we proposed a novel reliability mechanism called the quasi reaction-diffusion model to explain the generation of Delta N-it, which also explains the unclear phenomena of mobility boost.
Bipolar resistive switching effect in Gd(2)O(3) films for transparent memory application
(2011-07-01)
Liu, Kou-Chen
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Tzeng, Wen-Hsien
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Chang, Kow-Ming
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Chan, Yi-Chun
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Kuo, Chun-Chih
A transparent resistive random access memory based on ITO/Gd(2)O(3)/ITO capacitor structure is fabricated on glass substrate. The transparent memory exhibits reliable resistive switching for more than 1000 cycles, low operation voltage of -2 V/+2 V, and highly transmittance above 80% for visible light. From the TEM and XPS analysis, the asymmetry of the interfacial layer thickness is responsible for the asymmetric switching properties. The transitional multi-valance states of the bottom interfacial layer can serve as oxygen reservoir for oxygen migration back and forth under different polarity of applied bias. This work presents a candidate material Gd(2)O(3) for the application on the T-RRAM devices. (C) 2011 Elsevier B.V. All rights reserved.
Bipolar resistive switching effect in Gd2O3 films for transparent memory application
(2011-07-01)
Liu, Kou-Chen
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Tzeng, Wen-Hsien
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Chang, Kow-Ming
;
Chan, Yi-Chun
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Kuo, Chun-Chih
A transparent resistive random access memory based on ITO/Gd2O3/ITO capacitor structure is fabricated on glass substrate. The transparent memory exhibits reliable resistive switching for more than 1000 cycles, low operation voltage of -2 V/+2 V, and highly transmittance above 80% for visible light. From the TEM and XPS analysis, the asymmetry of the interfacial layer thickness is responsible for the asymmetric switching properties. The transitional multi-valance states of the bottom interfacial layer can serve as oxygen reservoir for oxygen migration back and forth under different polarity of applied bias. This work presents a candidate material Gd2O3 for the application on the T-RRAM devices. (C) 2011 Elsevier B.V. All rights reserved.
Characteristics of IGZO TFT Prepared by Atmospheric Pressure Plasma Jet Using PE-ALD Al2O3 Gate Dielectric
(2012-04-01)
Wu, Chien-Hung
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Chang, Kow-Ming
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Huang, Sung-Hung
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Deng, I-Chung
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Wu, Chin-Jyi
This letter proposes a novel atmospheric pressure plasma jet (APPJ) method for indium-gallium-zinc-oxide (IGZO) deposition and use of the plasma-enhanced atomic layer deposition (PE-ALD) Al2O3 as gate dielectric. A nonvacuum and simple APPJ system was demonstrated for channel material deposition. High-transmittance nanocrystalline IGZO thin films were obtained. Excellent electrical characteristics were achieved, including a low V-T of 0.71 V, a small subthreshold swing of 276 mV/dec, a mobility of 8.39 cm(2)/(V . s), and a large I-on/I-off ratio of 1 x 10(8).
Characteristics of zirconium oxide gate ion-sensitive field-effect transistors
(2007-07-01)
Chang, Kow-Ming
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Chao, Kuo-Yi
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Chou, Ting-Wei
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Chang, Chin-Tien
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電子工程學系及電子研究所
In this study. the zirconium oxide (ZrO2) membrane has been successfully applied as a pH-sensitive layer for ion-sensitive field-effect transistors (ISFETs). It exhibited an excellent response range of 56.7-58.3 mV/pH from the fixed current measurement using HP4156A. The ZrO2 membrane prepared by direct current (DC) sputtering was used as a pH-sensitive film that showed good surface adsorption with oxide and silicon. The pH sensitivities slightly decreased in 1 M NaCl solution; however. the device showed a perfect linear response of 52.5 mV/pH. The linear pH sensitivity response was measured between pH 1 to 13 in a buffer solution that was provided by Riedel-deHan.
Characterization of the low temperature activated N(+)/P junction formed by implant into silicide method
(2008-07-30)
Chang, Kow-Ming
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Lin, Jian-Hong
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Yang, Chih-Hsiang
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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
Shallow junction formation and low thermal budget control are important for advanced device manufacturing. Implant into silicide (IIS) method is a candidate to achieve both requirements. In this work we show that the high activation ability of the implant into nickel silicide method at low activated temperature is strongly related to the solid phase epitaxial regrowth (SPER) process. The SIMS, capacitance-voltage (C-V), four points probe (FPP), and current-voltage (I-V) measurements are combined to demonstrate that the SPER process of the IIS method is starting from the silicide/silicon (M/S) interface. The best N(+)/P interface is formed when SPER is complete. After SPER process finished, additional thermal budget may cause junction performance degradation at the temperature higher than 550 degrees C. (C) 2008 Elsevier B. V. All rights reserved.
Characterization of the low temperature activated P+/N junction formed by implant into silicide method
(2007)
Chang, Kow-Ming
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Lin, Jian-Hong
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Yang, Chih-Hsiang
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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
Characterization of the low temperature dopant activation behavior at NiSi/silicon interface formed by implant into silicide method
(2008-07-30)
Chang, Kow-Ming
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Lin, Jian-Hong
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Sun, Cheng-Yen
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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
Process temperature and thermal budget control are very important for high-k dielectric device manufacturing. This work focuses on the characteristics of low temperature activated nickel silicide/silicon (M/S) interface formed by implant into silicide (IIS) method. By combining SIMS, C-V, I-V, and AFM measurements in this work, it provides a clear picture that the high dopant activation ratio can be achieved at low temperature (below 600 degrees C) by IIS method. From SIMS and C-V measurements, high dopant activation behavior is exhibited, and from I-V measurement, the ohmic contact behavior at the M/ S junction is showed. AFM inspection displays that under 2nd RTA 700 degrees C 30 s no agglomeration occurs. These results suggest that IIS method has the potential to integrate with high-k dielectric due to its low process temperature. It gives an alternate for future device integration. (C) 2008 Elsevier B. V. All rights reserved.
Cu(In,Ga)Se-2 thin films preparation from CuGa-In metallic alloy and Se thin film by atmosphere pressure plasma deposition system
(2012)
Chang, Kow-Ming
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Ho, Po-Ching
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Yang, Kuo-Hui
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Wu, Shen-Bin
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Liu, Chi-Hung
An atmosphere pressure plasma (APP) deposition system with dielectric barrier discharge (DBD) is proposed for deposition selenium thin films on CuGa-In metallic precursors and transformed into Cu(In,Ga)Se-2 (CIGS) thin films by rapid thermal process (RTP). Morphologies and thicknesses of selenium thin films deposited on In/CuGa/Mo/SLG can be affected by plasma power which also has impact on crystallinity of CIGS absorber. With the increase in plasma power, CIGS grains tend to distribute non-uniformly. Plasma power of 100W has the smallest FWHM of the main peak (112). Insufficient selenium incorporation into precursors result in undesired phases such as Cu3Se2, Cu2Se and separation phase, CuGaSe2 compound. Compositions of optimal selenized CIGS thin film deposited by scanning 180times are Cu/(In+Ga) = 1.03 and Ga/(In+Ga) = 0.24.
Design of low-temperature CMOS-process compatible membrane fabricated with sacrificial aluminum layer for thermally isolated applications
(2007-03-15)
Chang, Kow-Ming
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Lin, Ren-Jie
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Deng, I-Chung
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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 the surface micromachining technique, residual stress and sticking effect play an important role in determining whether a microstructure is suspended or collapse during a release process. In this paper, we propose a simpler method for making suspended membranes for thermally isolated application by using cheap processing steps and compatible with CMOS-process; also, there are some simulations done to predict stiction as function of the anchor profile. It is demonstrated by fabricating the test structures of CMOS-process compatible surface micromachined bolometer using aluminum sacrificial layer with high yield and high throughput. The aluminum sacrificial layer provides some benefits including rapid wet-etching and high wet-etching selectivity with respect to dielectric materials. The residual stress and gravity of the microstructures are evaluated with structural simulations, and the sticking effect can be alleviated by an appropriate structure design and a release process. Once the residual stress is known, we can successfully use Coventorware simulations to predict a suspended membrane by controlling the anchor profile which contains sidewall conformal factor and sidewall angle. The simulation results are in good agreement with the experiments. (c) 2006 Elsevier B.V. All rights reserved.
Development of an Ion Sensitive Field Effect Transistor Based Urea Biosensor with Solid State Reference Systems
(2010-06-01)
Chang, Kow-Ming
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Chang, Chih-Tien
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Chan, Kun-Mou
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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
Development of FET-Type Reference Electrodes for pH-ISFET Applications
(2010)
Chang, Kow-Ming
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Chang, Chih-Tien
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Chao, Kuo-Yi
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Chen, Jin-Li
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電子工程學系及電子研究所
A reference field effect transistor (FET) fabrication method by using a perfluorosulfonated proton exchange membrane associated with ion-insensitive polymers is proposed. The single-layer film of the perfluorosulfonated polymer/photoresist composite among the eight films tested demonstrated the best performance of 5.8 mV/pH and 11.27 mV/pNa sensitivities. Meanwhile, the drift performances were 3.5 mV/h and less than 1 mV/h for the first and second 4 h tests. A high sensitivity of 52.1 mV/pH and a low interference of 4.61 mV/pNa were obtained in the range of pH 1-13 through the differential arrangement with ZrO(2) gate ion-sensitive field-effect transistors (ISFETs). Meanwhile, the transconductance match of the proposed reference FET/ISFET pair would simplify the differential readout circuits.
Effect of channel-width widening on a poly-Si thin-film transistor structure in the linear region
(2007-09-01)
Chang, Kow-Ming
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Lin, Gin-Ming
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電子工程學系及電子研究所
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奈米中心
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Department of Electronics Engineering and Institute of Electronics
This is the first paper to discuss the ON-state drain-current of a special thin-film transistor structure with a wide channel width and a narrow source/drain width in the linear region. The experimental results indicate that when the channel width is wider than the source/drain width, the side-channel current effect is generated. This effect increases the ON-state drain-current due to the additional current-flow paths existing in the side-channel regions and low channel resistance. As the side-channel width increases, the ON-state drain-current initially increases and then gradually becomes independent of the side-channel width when the side-channel width is larger than the effective side-channel width, which depends on the channel width and is largely independent of the source/drain width. This paper also demonstrates that the ON-state drain-current gain is directly proportional to the channel length and the ratio of the channel length to the source/drain width and dependent on the side-channel width.
Effect of ITO electrode with different oxygen contents on the electrical characteristics of HfOx RRAM devices
(2013-09-01)
Zhong, Chia-Wen
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Tzeng, Wen-Hsien
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Liu, Kou-Chen
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Lin, Horng-Chih
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Chang, Kow-Ming
In this study, the influence of indium tin oxide (ITO) top electrodes with different oxygen contents on the resistive switching characteristics of HfOx/TiN capacitor structure is investigated. Switching parameters, including set and reset voltage values, and high and low resistance values are highly related to the properties of ITO thin films. Higher resistance values in both states can be obtained when ITO thin films with higher oxygen contents are used as top electrodes; such values are accompanied by larger set voltages and fluctuating transient currents during the reset process. Based on the proposed filament model, we suggest that the switching mechanism of HfOx/TiN structure is attributed to the formation and rupture of conducting filamentary paths near the anodic side, which is highly correlated with the properties of the top electrode. The top electrode must be well determined to obtain reliable switching properties. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.