Browsing by Issue Date, starting with "2006-12-01"

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ESD-protection design with extra low-leakage-current diode string for RF circuits in SiGeBiCMOS process
(2006-12-01)
Ker, Ming-Dou
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Hsiao, Yuan-Wen
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Wu, Woei-Lin
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電機學院
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College of Electrical and Computer Engineering
Two low-leakage resistor-shunted diode strings Eire developed for use as power clamps in silicon-germanium (SiGe) BiCMOS technology. The resistors are used to bias the deep N-wells, significantly reducing the leakage current from the diode string. A methodology for selecting the values of the bias resistors is presented. For further reduction of the leakage current, an alternate design is presented: the resistor-shunted trigger bipolar power clamp. The power-clamp circuits presented herein may be used in cooperation with small double diodes at the I/O pins to achieve whole-chip electrostatic-discharge protection for RF ICs in SiGe processes.
Process and characteristics of fully silicided source/drain (FSD) thin-film transistors
(2006-12-01)
Lin, Chia-Pin
;
Hsiao, Yi-Hsuan
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Tsui, Bing-Yue
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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 this paper, high-performance fully silicided source/drain (FSD) thin-film transistors (TFTs) with FSD and ultrashort source/drain extension (SDE) fabricated by the implantto-silicide (ITS) technique are studied thoroughly. Using the ITS technique, not only the implantation damage but also the silicide spiking is avoided so that the thermal budget can be decreased obviously. The offstate current (I-off) of the FSD TFTs is equal to (n-channel) or smaller than (p-channel) that of the conventional TFTs. At onstate, due to the FSD and the SDE structure, the parasitic resistance of the S/D region and the carrier-injection resistance between silicide and channel are reduced. Therefore, superior onstate/offstate current ratio can be obtained. The influences of annealing temperature and time are also examined in this paper. A 600 degrees C/30-s rapid thermal annealing is sufficient to diffuse and activate dopants and, then, fabricate high-performance FSD TFTs. Excellent short-channel behavior of the FSD TFT is also confirmed. To conclude, the high-performance FSD TFT with low parasitic resistance fabricated by low-thermal-budget process is very promising for active-matrix liquid-crystal display, active-matrix organic light-emitting-diode display, and system-on-panel applications.
Optical transfer functions for specific-shaped apertures generated by illumination with a rectangular light pipe
(2006-12-01)
Cheng, Chu-Ming
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Chern, Jyh-Long
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光電工程學系
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Department of Photonics
We investigated the pupil functions of specific-shaped apertures generated by Lambertian illumination with a rectangular light pipe to derive the corresponding optical transfer functions (OTFs) in aberration-free and defocused optical systems. The semianalytical results indicate that the curves of the OTF of the optical system vary with the form of the shaped apertures that are generated by illumination with different geometric structures of light pipes and light sources. It was found that the OTF values of even-peak frequencies decrease when the Lambertian light source decreases. If there are a total of n X n individual apertures within a pupil, then n near-periodical peaks will appear on the OTF curve. It is evident that the values of the OTF remain almost unchanged even when the lengths of the light pipes are different. Furthermore, the geometric structure of the light pipe does not affect the resolution limit of the optical system, and under the condition of a larger defocused coefficient omega(20), the results of the defocused system can coincide with those of the aberration-free systems. (c) 2006 Optical Society of America.
Parallel implementation of a three-dimensional electrostatic PIC-MCC method using an unstructured tetrahedral mesh
(2006-12-01)
Wu, J. -S.
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Hsu, K. -H.
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機械工程學系
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Department of Mechanical Engineering
A parallel three-dimensional electrostatic particle-in-cell Monte Carlo Collision (PIC-MCC) code using an unstructured tetrahedral mesh is developed and validated in this paper. Poisson's equation is discretized by a nodal finite element method using a linear interpolation function. Charged-particle motion is traced cell by Cell using a leap-frog method and the Boris scheme. Code is validated using quasi-one-dimensional radiofrequency gas discharge by observing the bi-Maxwellian electron energy probability distribution function at low pressure. Parallel performance of the PIC code is tested using a three-dimensional radiofrequency gas discharge on a PC-cluster system. Results show that parallel efficiency of 83% can be achieved at 32 processors with dynamic domain decomposition.
New Cu/Mo/Ge/Pd ohmic contacts on highly doped n-GaAs for InGaP/GaAs heterojunction bipolar transistors
(2006-12-01)
Chang, Chun-Wei
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Hseh, Tung-Ling
;
Chang, Edward Yi
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材料科學與工程學系
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Department of Materials Science and Engineering
The feasibility of using novel Cu/Mo/Ge/Pd ohmic contacts on n+-GaAs for heterojunction bipolar transistors (HBTs) is investigated. The electrical and material characteristics of the Cu/Mo/Ge/Pd/n(+)-GaAs structure were studied. After thermal annealing at 350 degrees C, the specific contact resistances of the copper ohmic contacts Cu/Mo/Ge/Pd were measured to be 2.8 x 10(-7) Omega cm(2). Judging from the data of sheet resistance, X-ray diffraction analysis, Auger electron spectroscopy, and transmission electron microscopy, the Cu/Mo/Ge/Pd contact structure was very stable after annealing at 350 degrees C. However, after 400 degrees C annealing, the reaction of copper with the underneath layers started to occur and formed MoGe2, Cu3Ga and Ge3CU phases. An InGaP/GaAs HBT with C'u/Mo/Ge/Pd contact metals was fabricated and compared with an HBT fabricated with traditional Au/Ni/Ge/Au contact metals. These two kinds of HBTs showed similar device characteristics. After reaching thermal stability and per-forming a high current-accelerated stress test at a current density of 120 kA/cm(2) for 24h, the device with the Cu/Mo/Ge/Pd ohmic contacts still exhibits excellent electrical characteristics.
Comparison on the sensitivity of fiber-optic SONET OC-48PIN-TIAs measured by using synchronous modulation intermixing technique and bit error rate tester
(2006-12-01)
Liao, Yu-Sheng
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Lin, Gong-Ru
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光電工程學系
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Department of Photonics
A novel synchronous modulation and intermixing (SMIM) technique is presented to measure the sensitivity and evaluate the bit error rate (BER) of p-i-n photodiode receivers with transimpedance amplifiers (PIN-TIAs) without using any BER tester (BERT). When using the SMIM technique, the premier receiving measurement performance from the data rates of the synchronous optical network OC-3 to OC-48 was demonstrated. For general TO-46 packaged PIN-TIAs; a minimum intermixed voltage of 12.5 mV obtained by the SMIM method is equivalent to a sensitivity of -31 dBm at a requested BER of < 10(-10) determined by BERT. The relationship between the monitoring voltage and the BER of the optical pattern received by the PIN-TIA and limited amplifier is estimated. The error of the measured voltage is 0.28 mV, which corresponds to the error sensitivity of 0.09 dB. This would show the accuracy of the simplified and low-cost SMIM technique for in situ diagnostics on a mass-production line.
Study of traps in polydiacetylene based devices using TSC technique
(2006-12-01)
Renaud, C.
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Huang, C. H.
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Zemmouri, M.
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Le Rendu, P.
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Nguyen, T. P.
Trap parameters in poly(1-(3,4-difluorophenyl)-2-(4-pentylcyclohexylphenyl)acetylene) (PDPA-2F) based devices have been investigated by using the thermally stimulated current (TSC) technique. The device structure is ITO-PEDOT-(PDPA-2F)-M, where M stands for the cathode metal (Al, Ca/Al, and Au). The results reveal at least three TSC peaks in devices denoted as peaks A, B and C. Comparing trap parameters in ITO-PEDOT-(PDPA-2F)-Au hole-only device and ITO-PEDOT-(PDPA-2F)-Ca Al (Al) bipolar devices, we assigned A and B trap types to hole-like traps and C type traps to electron-like traps. The trap densities are in the range of 10(15)-10(17) cm(-3) and the trap levels are 0.12 eV (A type traps), 0.36 eV (B type traps), and 0.25 eV (C type traps).
A semicylindrical capacitive sensor with interface circuit used for flow rate measurement
(2006-12-01)
Chiang, Cheng-Ta
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Huang, Yu-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 this paper, a semicylindrical capacitive sensor with an interface circuit used for flow rate measurement is proposed. The numerical analysis method to calculate the capacitance of the semicylindrical capacitive sensor is analyzed and discussed. The picofarad-range capacitive variation of the semicylindrical capacitive sensor can be detected and converted into voltage variation by the interface circuit. Besides, the interface circuit is compact enough to simplify the circuit complexity and could be easily implemented for flow rate measurement. All the functions of the capacitive sensing method of the semicylindrical capacitive sensor used for flow rate measurement are proved successfully through HSPICE simulation. Measurement results have successfully confirmed the correct functions and performance of the semicylindrical capacitive sensor with an interface circuit used for flow rate measurement, which ranges from 0.136 to 4.746 L/min, on the liquid crystal display panel coating machine.
CBD oriented commuters' mode and residential location choices in an urban area with surface streets and rail transit lines
(2006-12-01)
Hsu, Chaug-Ing
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Guo, Shwu-Ping
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
This study formulates a commuters' mode and route choice model as well as a households' residential choice model on a two-dimensional space. The commuters' mode and route choice model assumes that commuters select the mode and route alternative based on the least generalized travel cost. The households' residential choice model is formulated to maximize households' residential utilities subject to time and budget constraints. A simulation method is adopted to simulate household choice behavior and solve the households' residential location choice model with two-dimensional decision variables to prevent aggregation bias. A case study for Taipei metropolitan area is illustrated to analyze the variations of residential location choices for households working in the central business district (CBD) after different lines of Taipei Rapid Transit System are completed at various stages. Results indicate that (1) there is increased attraction of households in cities of Taipei County such as Pan-Chiao, Chung-Ho, Yong-Her, and Hsin-Tien due to the completion of rail transit networks and (2) residential locations better served by rail transit lines attract more households; thereby, resulting in higher residential densities.
(C)over-right-arrow(4)-decompositions of D-vP and D-v boolean OR P where P is a 2-regular subgraph of D-v
(2006-12-01)
Pu, Liqun
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Fu, Hung-Lin
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Shen, Hao
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應用數學系
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Department of Applied Mathematics
In this paper, we extend the study of C-4-decompositions of the complete graph with 2-regular leaves and paddings to directed versions. Mainly, we prove that if P is a vertex-disjoint union of directed cycles in a complete digraph D-v, then D-vP and D-v boolean OR Pcan be decomposed into directed 4-cycles, respectively, if and only if v(v-1) - vertical bar E(P)vertical bar = 0 (mod 4) and v(v-1) + vertical bar E(P)vertical bar = 0 (mod 4) where vertical bar E(P)vertical bar denotes the number of directed edges of P, and v >= 8.
Numerical simulation and comparison of electrical characteristics between uniaxial strained bulk and SOI FinFETs
(2006-12-01)
Li, Yiming
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電信工程研究所
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Institute of Communications Engineering
In this paper, electrical characteristics of 25 nm strained fin-typed field effect transistors (FinFETs) with oxide-nitride-stacked-capping layer are numerically studied. The FinFETs are fabricated on two different wafers, one is bulk silicon and the other is silicon-on-insulator (SOI) substrate. A three-dimensional device simulation is performed by solving a set of density-gradient-hydrodynamic equations to study device performance including, such as the drain current characteristics (the I-D-V-G and I-D-V-D curves), the drain-induced barrier height lowering, and the subthreshold swing. Comparison between the strained bulk and SOI FinFETs shows that the strained bulk FinFET is promising for emerging multiple-gate nanodevice era according to the manufacturability point of view.
The controllable ball joint mechanism
(2006-12-01)
Tung, Yung Cheng
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Chieng, Wei-Hua
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Ho, ShrWai
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機械工程學系
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Department of Mechanical Engineering
A controllable ball joint mechanism with three rotational degrees of freedom is proposed in this paper. The mechanism is composed of three bevel gears, one of which rotates with respect to a fixed frame and the others rotate with respect to individual floating frames. The output is the resultant motion of the differential motions by the motors that rotates the bevel gears at the fixed frame and the floating frames. The mechanism is capable of a large rotation, and the structure is potentially compact. The necessary inverse and forward kinematic analyses as well as the derivation of kinematic singularity are provided according to the kinematical equivalent structure described in this paper.
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
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Deng, I-Chung
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Chen, Jin-Bo
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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.
On relocation problems with multiple identical working crews
(2006-12-01)
Kononov, A. V.
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Lin, B. M. T.
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
The relocation problem was formulated from a public housing project. In its basic form, a set of buildings needed to be torn down and erected by a single working crew. Given a fixed budget, the relocation problem seeks to determine a feasible reconstruction sequence of the old buildings. This problem has been shown to be mathematically equivalent to the classical two-machine flowshop of makespan minimization. In this paper, we consider a variant where multiple working crews are available for the redevelopment project. Most of our results center on the situations where all buildings require the same redevelopment time. We first present a strong NP-hardness proof for the case with two working crews. Then, we give a negative result about the approximability of the studied problem. Approximation algorithms and associated performance-ratio analysis are designed for the cases with unbounded as well as bounded numbers of machines. (c) 2006 Elsevier B.V. All rights reserved.
A high visual quality sprite generator using intelligent blending without segmentation masks
(2006-12-01)
Kuo, I-Sheng
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
The sprite generator introduced in MPEG-4 blends frames by averaging, which will make places, that are always occupied by moving objects, look blurred. Thus, providing segmented masks for moving objects is suggested. Several researchers have employed automatic segmentation methods to produce moving object masks. Based on these masks, they used a reliability-based blending strategy to generate sprites. Since perfect segmentation is impossible, some ghost-like shadows will appear in the generated sprite. To treat this problem, in this paper, an intelligent blending strategy without needing segmentation masks is proposed. It is based on the fact that for each point in the generated sprite, the corresponding pixels in most frames belong to background and only few belong to moving objects. A counting schema is provided to make only background points participate in average blending. The experimental result shows that the visual quality of the generated sprite using the proposed blending strategy is close to that using manually segmented masks and is better than that generated by Lu-Gao-Wu method. No ghostlike shadows are produced. Furthermore, a uniform feature point extraction method is proposed to increase the precision of global motion estimation, the effectiveness of this part is presented by showing the comparison results with other existing method.
A hybrid particle swarm optimization for job shop scheduling problem
(2006-12-01)
Sha, D. Y.
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Hsu, Cheng-Yu
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工業工程與管理學系
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Department of Industrial Engineering and Management
A hybrid particle swarm optimization (PSO) for the job shop problem (JSP) is proposed in this paper. In previous research. PSO particles search solutions in a continuous solution space. Since the solution space of the JSP is discrete, we modified the particle position representation, particle movement, and particle velocity to better suit PSO for the JSP. We modified the particle position based on preference list-based representation, particle movement based on swap operator, and particle velocity based on the tabu list concept in our algorithm. Giffler and Thompson's heuristic is used to decode a particle position into a schedule. Furthermore, we applied tabu search to improve the solution quality. The computational results show that the modified PSO performs better than the original design, and that the hybrid PSO is better than other traditional metaheuristics. (c) 2006 Elsevier Ltd. All rights reserved.
Unstable vortex flow and new inertia-driven vortex rolls resulting from an air jet impinging onto a confined heated horizontal disk
(2006-12-01)
Hsieh, F. C.
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Wu, J. H.
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Hsieh, J. C.
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Lin, T. F.
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機械工程學系
An experiment combining flow visualization and temperature measurement is carried out here to investigate the possible presence of new inertia-driven vortex rolls and some unique characteristics of the time-dependent mixed convective vortex flow in a high-speed round air jet impinging onto a heated horizontal circular disk confined in a vertical cylindrical chamber. How the jet Reynolds and Rayleigh numbers and jet-to-disk separation distance affect the unique vortex flow characteristics is examined in detail. Specifically, the experiment is conducted for the jet Reynolds number varying from 0 to 1623 and Rayleigh number from 0 to 63,420 for the jet-to-disk separation distance fixed at 10.0, 20.0 and 30.0 mm. The results indicate that at sufficiently high Re-j the inertia-driven tertiary and quaternary rolls can be induced aside from the primary and secondary rolls. At an even higher Re-j the vortex flow becomes unstable due to the inertia-driven flow instability. Only for H = 20.0 mm the flow is also subjected to the buoyancy-driven instability for the ranges of the parameters covered here. Because of the simultaneous presence of the inertia- and buoyancy-driven flow instabilities, a reverse flow transition can take place in the chamber with H = 20.0 mm. At the large H of 30.0 mm the flow unsteadiness results from the mutual pushing and squeezing of the inertia- and buoyancy-driven rolls since they are relatively large and contact with each other. It is also noted that the critical Re-j for the onset of unsteady flow increases with AT for H = 10.0 and 20.0 mm. But for H = 30.0 mm the opposite is true and raising Delta T can destabilize the vortex flow. Based on the present data, flow regime maps delineating the temporal state of the flow are provided and correlating equations for the boundaries separating various flow regimes are proposed. (c) 2006 Elsevier Ltd. All rights reserved.
Synthesis and characterization of poly(fluorene-coalt-phenylene) containing 1,3,4-oxadiazole dendritic pendants
(2006-12-01)
Wu, Chung-Wen
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Sung, Hsiao-Hsien
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Lin, Hong-Cheu
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材料科學與工程學系
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Department of Materials Science and Engineering
A series of poly(fluorene-co-alt-phenylene)s containing various generations of dendritic oxadiazole (OXD) pendent wedges were synthesized by the Suzuki polycondensation of OY-D-functionalized 1,4-dibromophenylene with 9,9-dihexylfluorene-2,7-diboronic ester. The obtained polymers possessed excellent solubility in common solvents and good thermal stability. Photophysical studies showed that the dendronized polymers appended with higher generations of OXD dendrons exhibited enhanced photoluminescence efficiencies and narrower values of the full width at half-maximum. This was attributed to the shielding effect induced by the bulky dendiitic OXD side chains, which prevented self-quenching and suppressed the formation of aggregates/excimers. The energy transfer from the OXD dendrons to the polymer backbones was very efficient when excitation of the peripheral OXD dendrons resulted mainly in the polymer backbone emission alone. In particular, the photoluminescence emission intensities by the sensitized excitations of OXD dendrons in solid films of the polymers were all stronger than those by the direct excitations of their polymer conjugated backbones. (c) 2006 Wiley Periodicals, Inc.
Stochastic generation of hourly rainstorm events
(2006-12-01)
Wu, Shiang-Jen
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Tung, Yeou-Koung
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Yang, Jinn-Chuang
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土木工程學系
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Department of Civil Engineering
Occurrence of rainstorm events can be characterized by the number of events, storm duration, rainfall depth, inter-event time and temporal variation of rainfall within a rainstorm event. This paper presents a Monte-Carlo based stochastic hourly rainfall generation model considering correlated non-normal random rainstorm characteristics, as well as dependence of various rainstorm patterns on rainfall depth, duration, and season. The proposed model was verified by comparing the derived rainfall depth-duration-frequency relations from the simulated rainfall sequences with those from observed annual maximum rainfalls based on the hourly rainfall data at the Hong Kong Observatory over the period of 1884-1990. Through numerical experiments, the proposed model was found to be capable of capturing the essential statistical features of rainstorm characteristics and those of annual extreme rainstorm events according to the available data.
A novel self-aligned etch-stopper structure with lower photo leakage for AMLCD and sensor applications
(2006-12-01)
Liang, Chung-Yu
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Gan, Feng-Yuan
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Liu, Po-Tsun
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Yeh, F. S.
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Chen, Stephen Hsin-Li
In this letter, the authors introduce a novel self-aligned etch-stopper sidewall-contact hydrogenated amorphous silicon (a-Si: H) thin-film transistor (ESSC-TFT), which reduces the photo leakage current by more than one order of magnitude and increases the ON-OFF ratio to seven orders of magnitude under back light illumination. Such a TFT will enable high-resolution and high-brightness liquid-crystal displays (LCDs) for next-generation TV, monitor, notebook, and mobile-phone applications. This ESSC-TFT design reduces the volume of a-Si film in which the active region can totally be shielded by the gate metal resulting in the prevention from direct back light illumination. With the sidewall contact, the hole current is reduced due to the smaller contact area between drain/source and a-Si layer. As well as the source, drain parasitic intrinsic resistance of a-Si can be also lessened by the ESSC-TFT structure. Although the defects between etched a-Si and n(+) a-Si film may degrade the ON current, the ESSC-TFT still exhibits higher ON-OFF ratio and lower leakage than the one in traditional etch-stopper (ES)-TFT structure. The ESSC-TFT structure can be used not only for TFT-LCD application but also for the applications that demand high ON-OFF ratio and low-leakage device, such as X-ray image sensor.