Browsing by Author "Chang, Yao-Jen"

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62nm CW wavelength-selectable erbium-doped fiber compound-ring laser with stable single-mode output
(2019-12-01)
Yeh, Chien-Hung
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Chang, Yao-Jen
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Lin, Wen-Piao
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Xie, Yue-Ru
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Luo, Chien-Ming
In this demonstration, an erbium-doped fiber (EDF) based laser with stable, wide and wavelength-selectable single-longitudinal-mode (SLM) performances is designed and demonstrated. Here, to achieve SLM oscillation, a compound-ring scheme is constructed in the EDF laser cavity serving as a mode-restriction-filter for densely side-mode suppression. Moreover, the continuous-wave tunability can be scaled from 1520.0 to 1582.0 nm by using the proposed compound-ring scheme and commercial C-band EDF amplifier. In the measurement, the output stability and 3 dB Lorentzian linewidth of each lasing wavelength in the proposed EDF compound-ring laser have also been discussed.
A Bayesian hierarchical detection framework for parking space detection
(2008)
Huang, Ching-Chun
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Wang, Sheng-Jyh
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Chang, Yao-Jen
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Chen, Tsuhan
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電子工程學系及電子研究所
hi this paper, a 3-layer Bayesian hierarchical detection framework (BHDF) is proposed for robust parking space detection. In practice, the challenges of the parking space detection problem come from luminance variations, inter-occlusions among cars, and occlusions caused by environmental obstacles. Instead of determining the status of parking spaces one by one, the proposed BHDF framework models the inter-occluded patterns as semantic knowledge and couple local classifiers with adjacency constraints to determine the status of parking spaces in a row-by-row manner. By applying the BHDF to the parking space detection problem, the available parking spaces and the labeling of parked cars can be achieved in a robust and efficient manner. Furthermore, this BHDF framework is generic enough to be used for various kinds of detection and segmentation applications.
A fiber Bragg grating based passive semicircular sensor architecture with fault monitoring
(2019-03-01)
Yeh, Chien-Hung
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Chang, Yao-Jen
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Huang, Tzu-Jung
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Yang, Zi-Qing
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Chow, Chi-Wai
In the investigation, we investigate a fiber Bragg grating (FBG) based semicircular sensor architecture with fiber fault monitoring experimentally. Two erbium-doped fiber amplifiers (EDFAs) are used in the monitoring center to generate a broadband light source for sensing the strain and temperature simultaneously. Here, we utilize six FBG based sensors with different reflected wavelength for proof-of-concept demonstration. There is no optical filter used in the FBG sensor system for wavelength-selection. In addition, the proposed sensor system can monitor one to two fiber faults. In the measurement, the temperature-and strain-induced changes are also analyzed and discussed. Therefore, the proposed multiple FBG based semicircular sensor system not only can sense the temperature and strain simultaneously, but also can be used to monitor where is the fiber fault.
A Novel Flexible 3-D Heterogeneous Integration Scheme Using Electroless Plating on Chips With Advanced Technology Node
(2015-12-01)
Hu, Yu-Chen
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Lin, Chun-Pin
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Chang, Yao-Jen
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Chang, Nien-Shyang
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Sheu, Ming-Hwa
A novel 3-D chip-level heterogeneous integration scheme for low cost and rapid pilot demonstration is proposed in this paper. The conventional Bumping fabrication is done at wafer level. However, due to the high cost of whole wafer, opting for chips with advanced technology node is a better alternative. Therefore, with the difficulties of the bumping process at chip level, 3-D heterogeneous integration by chip stacking faces challenges. This paper presents a novel heterogeneous integration platform by using electroless plating on chips and pillar bump on wafers before stacking. This integration platform can be applied to chip-to-chip or chip-to-wafer scheme when chips are fabricated from costly advanced technology node.
A Selectable Single-Mode Erbium Laser With Power-Flattened Output Employing Dual-Sagnac-Ring
(2019-01-01)
Yeh, Chien-Hung
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Lin, Wen-Piao
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Chang, Yao-Jen
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Xie, Yue-Ru
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Luo, Chien-Ming
To achieve wavelength-selectable and stable erbium-doped fiber (EDF) laser, a dual-Sagnac-ring configuration is designed to reach single-longitudinal-mode (SLM) oscillation and power-flattened output simultaneously. The presented and experimentally demonstrated EDF laser can also obtain the output power of 7.5 to 11.8 dBm in the continuous-wave (CW) tunability of 1523.0 to 1571.0 nm. Here, the power variation of lasing wavelength can be below than 1.0 dB over a wide working range of 1525.0-1565.0 nm for power-flattened output. Moreover, the 3-dB spectrum linewidth of presented EDF-based laser is measured in the range of 16.4-22.2 kHz via the Lorentzian fitting.
A Wafer-Level Three-Dimensional Integration Scheme With Cu TSVs Based on Microbump/Adhesive Hybrid Bonding for Three-Dimensional Memory Application
(2012-06-01)
Ko, Cheng-Ta
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Hsiao, Zhi-Cheng
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Chang, Yao-Jen
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Chen, Peng-Shu
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Hwang, Yu-Jiau
Thin wafer/chip stacking with vertical interconnect by a Cu through-silicon via (TSV) and a Cu/Sn microjoint is one of the candidates for 3-D integration. The insertion loss of the two-chip stack was evaluated with different TSV pitches, microbump diameters, and chip thicknesses to realize the signal transmission effects in high-speed digital signaling via TSV and microjoint interconnection. In addition, a wafer-level 3-D integration scheme with Cu TSVs based on Cu/Sn microbump and BCB adhesive hybrid bonding was demonstrated. Key technologies, including TSV interconnection, microbumping, hybrid bonding, wafer thinning, and backside RDL formation, were well developed and integrated to realize 3-D integration. This paper presents a complete study of the structure design, the process condition, and the electrical and reliability assessment of the wafer-level 3-D integration scheme. This 3-D integration scheme with excellent electrical performance and reliability provides a promising solution for 3-D memory application.
Action Research as a Bridge Between Two Worlds: Helping The NGOs and Humanitarian Agencies Adapt Technology to Their Needs
(2010-06-01)
Chang, Yao-Jen
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Liao, Rui-Hua
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Wang, Tsen-Yung
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Chang, Yao-Sheng
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經營管理研究所
This paper reflects upon the process of introducing social media systems into supported employment programs for peoples with severe mental illness in Taipei. Such intervention represents the encounter of two different worlds that are often-unknown to each other, i.e. IT student engineers and job coaches in NGOs. With the participatory and cyclic feature of action research approach, the process can be divided into three stages: technology-led stage, mutual infusion stage, and service-led stage. The focus of this research is to illustrate how action research provides a site for the infusion of two different horizons, that is technology experts in academia and social service providers in NGOs. The existing problems in the use of IT within NGOs were studied and changes through co-inquiry and interventions were implemented towards better utilization of IT and higher levels of service qualities. The researchers utilized an action research approach to investigate the problems, plan the actions, intervene, assess the effectiveness resulting from the actions, and specify learning outcomes.
Al2O3 Interface Engineering of Germanium Epitaxial Layer Grown Directly on Silicon
(2013-01-01)
Tan, Yew Heng
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Yew, Kwang Sing
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Lee, Kwang Hong
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Chang, Yao-Jen
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Chen, Kuan-Neng
The quality of germanium (Ge) epitaxial film grown directly on silicon (Si) substrate is investigated based on the electrical properties of a metal-oxide-semiconductor capacitor (MOSCAP). Different thermal cycling temperatures are used in this study to investigate the effect of temperature on the Ge film quality. Prior to high-k dielectric deposition, various surface treatments are applied on the Ge film to determine the leakage current density using scanning tunneling microscopy. The interface trap density (D-it) and leakage current obtained from the C-V and I-V measurements on the MOSCAP, as well as the threading dislocation density (TDD), show a linear relationship with the thermal cycling temperature. It is found that the Ge epitaxial film that undergoes the highest thermal cycling temperature of 825 degrees C and surface treatment in ultraviolet ozone, followed by germanium oxynitride (GeOxNy) formation, demonstrates the lowest leakage current of similar to 2.3 x 10(-8) A/cm(2) (at -2 V), D-it similar to 3.5 x 10(11) cm(-2)/V, and TDD < 10(7) cm(-2).
Asymmetric Low Temperature Bonding Structure Using Ultra-thin Buffer Layer Technique for 3D Integration
(2016)
Liang, Hao-Wen
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Yu, Ting-Yang
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Chang, Yao-Jen
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Chen, Kuan-Neng
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電子工程學系及電子研究所
Wafer-level Sn/In-Cu bonding structure with Ni ultra-thin buffer layer is investigated to achieve a reduction in solder thickness, bonding temperature and duration. Furthermore, the asymmetric bonding structure is able to separate the manufacturing process of solder and electrical isolation layer. It is a promising approach for the application on hybrid bonding of three-dimensional integration.
Asymmetric Low Temperature Bonding Structure with Thin Solder Layers Using Ultra-Thin Buffer Layer
(2018-08-01)
Yu, Ting-Yang
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Liang, Hag-Wen
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Chang, Yao-Jen
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Chen, Kuan-Neng
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電子工程學系及電子研究所
Asymmetric Cu to In/Sn bonding structure with Ni ultrathin buffer layer (UBL) on Cu side is investigated in this research. The usage of Ni UBL slows down intermetallic compound (IMC) formation during bonding. Asymmetric structure can separate electrical isolation and solder process to avoid interaction, which can prevent IMC formation during polymer curing. A well-bonded asymmetric structure can be achieved with submicron solder by 150 degrees C bonding for 15 min. The structure shows the potential for low temperature hybrid bonding technology in high-density three-dimensional (3D) integration.
Backside-Process-Induced Junction Leakage and Process Improvement of Cu TSV Based on Cu/Sn and BCB Hybrid Bonding
(2013-03-01)
Chang, Yao-Jen
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Ko, Cheng-Ta
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Yu, Tsung-Han
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Chiang, Cheng-Hao
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Chen, Kuan-Neng
Wafer-level 3-D integration using Cu through-silicon vias (TSVs) and fine-pitch Cu/Sn-BCB hybrid bonding is investigated with electrical leakage current. With the well-fabricated Cu TSVs and Cu/Sn bond structures, the leakage current path in this scheme due to backside process was found, and the corresponding mechanism is discussed. The leakage current can be solved by the modified backside process. The improved 3-D integration scheme shows extremely low leakage current and no visible defects inside Cu TSV.
Bidirectional free space optical communication (FSO) in WDM access network with 1000-m supportable free space link
(2019-03-15)
Yeh, Chien-Hung
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Guo, Bo-Shen
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Chang, Yao-Jen
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Chow, Chi-Wai
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Gu, Chong-Sin
In this demonstration, we propose and investigate experimentally a bidirectional wavelength-division-multiplexed (WDM) free space optical communication (FSO) system integrated with fiber access network for wireless traffics. Here, there are four 10 Gbit/s on-off keying (OOK) WDM-FSO signals would propagate through a 25 km single-mode fiber (SMF) transmission and a 6 m free space transmission length for the bidirectional downstream and upstream FSO traffics. Moreover, an accurately simulation of detected powers of FSO wavelength under different free space transmission lengths can be estimated based on the proposed WDM-FSO system architecture. Therefore, according to the experimental and simulated results, the bidirectional WDM-FSO transmission can achieve 1000 m free space transmission length based on the obtained power sensitivity of each FSO signal.
Comparing Cyclic Tension-Compression Effects on CoCrFeMnNi High-Entropy Alloy and Ni-Based Superalloy
(2019-08-01)
Lam, Tu-Ngoc
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Chou, You-Shiun
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Chang, Yao-Jen
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Sui, Tsung-Ruei
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Yeh, An-Chou
An equal-molar CoCrFeMnNi, face-centered-cubic (fcc) high-entropy alloy (HEA) and a nickel-based superalloy are studied using in situ neutron diffraction experiments. With continuous measurements, the evolution of diffraction peaks is collected for microscopic lattice strain analyses. Cyclic hardening and softening are found in both metallic systems. However, as obtained from the diffraction-peak-width evolution, the underneath deformation mechanisms are quite different. The CoCrFeMnNi HEA exhibits distinct lattice strain and microstructure responses under tension-compression cyclic loadings.
Conductivity enhancement of multiwalled carbon nanotube thin film via thermal compression method
(2014-08-29)
Tsai, Wan-Lin
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Wang, Kuang-Yu
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Chang, Yao-Jen
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Li, Yu-Ren
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Yang, Po-Yu
For the first time, the thermal compression method is applied to effectively enhance the electrical conductivity of carbon nanotube thin films (CNTFs). With the assistance of heat and pressure on the CNTFs, the neighbor multiwalled carbon nanotubes (CNTs) start to link with each other, and then these separated CNTs are twined into a continuous film while the compression force, duration, and temperature are quite enough for the reaction. Under the compression temperature of 400 degrees C and the compression force of 100 N for 50 min, the sheet resistance can be reduced from 17 to 0.9 k Omega/sq for the CNTFs with a thickness of 230 nm. Moreover, the effects of compression temperature and the duration of thermal compression on the conductivity of CNTF are also discussed in this work.
Development and Electrical Investigation of Novel Fine-Pitch Cu/Sn Pad Bumping Using Ultra-Thin Buffer Layer Technique in 3D Integration
(2015)
Hsieh, Yu-Sheng
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Chang, Yao-Jen
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Chen, Kuan-Neng
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電機學院
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College of Electrical and Computer Engineering
A high yielding fine-pitch submicron Cu/Sn bonding scheme has been successfully demonstrated. With inserting the ultra-thin buffer layer, near sub-micron thickness Cu/Sn pad bonding can be achieved. The fine pitch Cu/Sn interconnects can be also further extended. The modified Kelvin feature in chip level and tens of thousands series interconnects per chip with a density of 3.4 x 10(5)/cm(2) in wafer level are fabricated and completely investigated on electrical characteristics. Several critical reliability assessments, such as TCT and unbias HAST, are also investigated the variation and standard error of the fine-pitch pad bonding scheme. With excellent mechanical properties, bonding quality, electrical and reliability results, the approach is suitable for future 3D vertical interconnects.
Development and Investigation of Ultra-Thin Buffer Layers Used in Symmetric Cu/Sn Bonding and Asymmetric Cu/Sn-Cu Bonding for Advanced 3D Integration Applications
(2017-01-01)
Chen, Hsiu-Chi
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Kho, Yi-Tung
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Huang, Yen-Jun
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Hsieh, Yu-Sheng
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Chang, Yao-Jen
In this work, a particular ultra-thin buffer layer (UBL) with various thickness ranging from 10 nm to 100 nm and different materials including Co, Ni, Pd and Ti is inserted between Cu/Sn to delay the interdiffusion prior to eutectic bonding. The efficacy of the buffer layer and the bonding quality are systematically conferred using microstructure imaging, material analysis, and electrical performance. In addition to symmetric Cu/Sn bonding with UBL, an asymmetric Cu/Sn-Cu bonding which is proposed to relieve the heat enhanced interdiffUsion issues thereby enhancing the reliability performance is demonstrated with the assistance of UBL technology.
Deviatoric deformation kinetics in high entropy alloy under hydrostatic compression
(2019-07-05)
Huang, E-Wen
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Lin, Chih-Ming
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Juang, Jenh-Yih
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Chang, Yao-Jen
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Chang, Yuan-Wei
An equiatomic CoCrFeMnNi high-entropy alloy under hydrostatic compression is investigated using insitu angular-dispersive X-ray diffraction to explore the polymorphism in high entropy alloy systems. The metallic system is of face-centered-cubic structure at ambient condition and applied hydrostatic pressures up to 20 GPa via diamond anvil cell. The angle-resolved diffraction-intensity evolutions of multiple diffraction peaks were collected simultaneously to elucidate the phase stability examinations. The phase transformation from face-centered-cubic to hexagonal-close-packed structure was evidently observed in CoCrFeMnNi alloy accompanied by a deviatoric strain subjected to the hydrostatic compression. We found lattice-asymmetric crossover before and after the phase transformation subjected to hydrostatic compression surroundings. Deviatoric strain triggers fcc-hcp phase transformation as local heterogeneity-driven lattice distortion is significant for CoCrFeMnNi alloy. (c) 2019 The Authors. Published by Elsevier B.V.
Electrical and Reliability Investigation of Cu TSVs With Low-Temperature Cu/Sn and BCB Hybrid Bond Scheme
(2013-01-01)
Chang, Yao-Jen
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Ko, Cheng-Ta
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Chen, Kuan-Neng
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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
A wafer-level 3-D integration scheme using Cu through-silicon vias (TSVs) and fine-pitch Cu/Sn-BCB hybrid bonding was developed and investigated with electrical characterization and reliability assessment. The hybrid bonding could be achieved below 250 degrees C. Low Kelvin resistance and stable daisy chain resistance were achieved in 5- and 10-mu m TSV test structures across the whole wafer. Without obvious deterioration in reliability test results, the integrated Cu TSV and hybrid bond scheme can be potentially designed for 3-D integration applications.
Electrical Investigation and Reliability of 3D Integration Platform using Cu TSVs and Micro-Bumps with Cu/Sn-BCB Hybrid Bonding
(2013)
Chang, Yao-Jen
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Ko, Cheng-Ta
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Hsiao, Zhi-Cheng
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Chiang, Cheng-Hao
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Fu, Huan-Chun
In this paper, the wafer-level three-dimensional (3-D) integration scheme using copper TSVs and fine-pitch Cu/Sn-BCB hybrid bonding is designed, fabricated, and completely investigated on electrical characteristics and stability. Key technologies in this 3D integration scheme include high aspect-ratio Cu TSV, fine-pitch Cu/Sn micro-bumps, 250 degrees C low temperature hybrid bonding, wafer thinning and backside RDL formation. The Kelvin and leakage current structures are designed for realization of fundamental electrical properties, and the daisy chain feature is designed for stability evaluation with several reliability tests. All the samples pass the 1000-cycle thermal cycling test, humidity test, and multiple AC current stressing. This scheme shows a significant leakage current improvement after modifying backside process. The stable reliability results and excellent electrical characteristics indicate that the 3D integration scheme has the excellent sealing ability against oxidation and corrosion, and could be potentially applied for future mass production.
Element Effects on High-Entropy Alloy Vacancy and Heterogeneous Lattice Distortion Subjected to Quasi-equilibrium Heating
(2019-10-15)
Huang, E-Wen
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Chou, Hung-Sheng
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Tu, K. N.
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Hung, Wei-Song
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Tu-Ngoc Lam
We applied Simmons-Balluffi methods, positron measurements, and neutron diffraction to estimate the vacancy of CoCrFeNi and CoCrFeMnNi high-entropy alloys (HEAs) using Cu as a benchmark. The corresponding formation enthalpies and associated entropies of the HEAs and Cu were calculated. The vacancy-dependent effective free volumes in both CoCrFeNi and CoCrFeMnNi alloys are greater than those in Cu, implying the easier formation of vacancies by lattice structure relaxation of HEAs at elevated temperatures. Spatially resolved synchrotron X-ray measurements revealed different characteristics of CoCrFeNi and CoCrFeMnNi HEAs subjected to quasi-equilibrium conditions at high temperatures. Element-dependent behavior revealed by X-ray fluorescence (XRF) mapping indicates the effect of Mn on the Cantor Alloy.