Browsing by Issue Date, starting with "2006-02-23"

Now showing 1 - 20 of 63674

Solar-pumped active device
(2006-02-23)
Chi, Sien
;
Chen, Nan-Kuang
;
Shy, Jow-Tsong
The present invention provides a solar-pumped active device which utilizes a holographic antenna grating on a solar energy silicon substrate to select specific diffracted wavelength and couple pump wavelength in an approximately vertical way and converge the pump wavelength to excite an optical gain medium so that an optical amplifier or a laser can be obtained. The present invention requires no big size and is flexible over the surface shape and is suitable for free space optical communications on the ground and satellite optical communications. It means that the holographic antenna grating can be applied on the top floor of a building or on the glass surface of an outer wall. If it is applied to a satellite, the present invention can be deposited on a solar energy cell substrate to form a high optical amplification so that not only the electricity required in satellite optical communications can be reduced, but also a high-speed and large capacity of data can be transferred between satellites.
Effect of deposition temperature and oxygen flow rate on properties of low dielectric constant SiCOH film prepared by plasma enhanced chemical vapor deposition using diethoxymethylsilane
(2006-02-24)
Cheng, YL
;
Wang, YL
;
Hwang, GJ
;
O'Neill, ML
;
Karwacki, EJ
Low dielectric constant (Low-k) films (SiCOH) were deposited from diethoxymethylsiliane [DEMS; SiH(CH3) (OC2H5)(2)] which has two ethoxy groups along with one methyl group attached to the silicon atoms. The deposited films have been characterized for different oxygen flows, ranging from 50 to 250 standard cubic centimeters per minute (seem). The growth rate is increased with the increasing oxygen (O-2) flow. The absorbance spectrum of Fourier transform infrared spectroscopy shows that the frequency of Si-O stretching vibration mode in the SiCOH film is shifted to a higher wave number with the increase of oxygen flow. It is deduced that the oxygen does not participate in a simple oxidative mechanism, and has no apparent impact on the methyl content even if the relative Si-O content of the deposited films is up to an O-2/DEMS flow rate ratio of 1:1. Also, the refractive index is decreased with increasing the oxygen flow and slightly increased with the deposition temperature. The dielectric constant of the SiCOH is investigated between 2.7 and 3.2, depending on the deposition temperature and O-2/DEMS flow rate ratio, which is lower than that of the current OSG films (k=2.9-3.3). SiCOH films deposited with DEMS only exhibit higher mechanical hardness and lower leakage current than those deposited with both DEMS and oxygen. (c) 2005 Elsevier B.V. All rights reserved.
Investigation of overpotential and seed thickness on damascene copper electroplating
(2006-02-24)
Chen, KW
;
Wang, YL
;
Chang, L
;
Li, FY
;
Chang, SC
This study found that higher overpotential from higher plating current density and a thinner seed layer resulted in more incorporation of sulfur impurities into a deposited copper film. Our results suggested that the higher plating overpotential resulted in smaller copper grains with more grain boundaries where more impurities were trapped. To achieve a defect-free filling in vias, the optimization of the plating current density and the seed layer thickness was necessary. A copper seed with thickness less than 30 generated a sulfur-rich copper film, while, thickness larger than 200 nm for 0.13-nm technologies, the copper seed led to a poor gapfilling with a void after electroplating. (c) 2005 Elsevier B.V. All rights reserved.
The 3rd Asian Conference on Chemical Vapor Deposition (3rd Asian-CVD), Taipei, Taiwan, November 12-14, 2004 - Preface
(2006-02-24)
Feng, ZC
;
Chen, CF
;
Kuo, CT
;
Williams, K
;
Shan, W
The study of diffusion and nucleation for COSi2 formation by oxide-mediated cobalt silicidation
(2006-02-24)
Chang, JJ
;
Liu, CP
;
Hsieh, TE
;
Wang, YL
;
材料科學與工程學系
The role of cobalt in oxide-mediated silicidation is studied in terms of diffusion and nucleation by varying annealing conditions, oxide thickness and implantation in Si substrate. Electroscopic imaging in transmission electron microscopy shows that SiOx act as a one-way diffusion barrier reducing the Co effective concentration at the cobalt silicide growth interface leading to CoSi2 as the first formation phase during silicidation. X-ray photoelectron spectroscopy analysis shows that unreacted Co coexists with CoSi2 at the interface between the SiOx layer and Si substrate, implying that Co diffusion rate is faster than CoSi, nucleation rate. An Si-implanted substrate can increase the CoSi2 nucleation rate and reduce the Co accumulation. (c) 2005 Elsevier B.V. All rights reserved.
A novel method for growing polycrystalline Ge layer by using UHVCVD
(2006-02-24)
Tu, CH
;
Chang, TC
;
Liu, PT
;
Yang, TH
;
Zan, HW
Poly-Ge grown on SiO2 substrates by using one-step ultra-high vacuum chemical vapor deposition (UHVCVD) process with thin Si nucleation layers at very low deposition temperature (350 degrees C) was demonstrated. The results demonstrated that the polycrystalline silicon (poly-Si) nucleation layer is needed for the growth of polycrystalline germanium (poly-Ge) on SiO2 substrates at low growth temperature. SEM image presents the films with uniform rain size and uniform thickness occurring in the samples. The grain size of poly-Ge is about 100 nm. The Raman shift spectrum and XRD spectrum also identified that films are high quality poly-Ge by using this method. (c) 2005 Elsevier B.V. All rights reserved.
Nanofabrication and the structure-property analyses of phase-change alloy-ended CNTs
(2006-02-24)
Wang, WH
;
Chao, KM
;
Teng, IJ
;
Kuo, CT
;
材料科學與工程學系
In order to cap the tip cavities of the open-ended carbon nanotubes (CNTs) with the phase-change alloy for potential applications as the nano-resolution storage media, the Co-assisted CNTs were first synthesized by electron cyclotron resonance chemical vapor deposition (ECR-CVD) with H-2 and CH4 as the gas sources. Then, the as-grown CNTs were post-treated in H-plasma atmosphere to remove the carbon layers covered on catalysts, and subsequently immersed in HNO3 solution to remove the catalysts from the tips. The open-ended CNTs with a bowl-like-shape tips were followed by coating with a phase-change alloy layer of GeSbTeSn via sputtering process, and then heat treated in vacuum for 30 min to trim the alloy off from the sidewalls of CNTs to obtain the alloy-ended CNTs. The structures and properties in each processing step were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and Auger electron spectroscopy (AES). The experimental results show that the well-oriented phase-change alloy-ended CNTs over a large area are fabricated successfully. Furthermore, the Auger analyses show the compositions of the phase-change alloys may be changed from Te-rich to Ge-rich after being capped on the tips of CNTs. (c) 2005 Elsevier B.V. All rights reserved.
Mn,Cd-metallothionein-2: A room temperature magnetic protean
(2006-02-24)
Chang, CC
;
Lee, SF
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Sun, KW
;
Ho, CC
;
Chen, YT
Naturally occurring metallothionein (MT) is a metal binding protein, which binds to seven Zn2+ through 20 conserved cysteines and forms two metal binding clusters with a Zinc-Blende structure. We demonstrate that the MT, when substituting the Zn2+ ions by Mn2+ and Cd2+, exhibits magnetic hysteresis loop observable by SQUID from 10 to 330 K. The magnetic moment may have originated from the bridging effect of the sulfur atoms between the metal ions that leads to the alignment of the electron spins of the Mn2+ ions inside the clusters. The protein backbone may restrain the net spin moment of Mn2+ ions from thermal fluctuation. The modified magnetic-metallothionein is a novel approach to creating molecular magnets with operating temperatures up to 330 K. (c) 2005 Elsevier Inc. All rights reserved.
Precipitates formation and its impact on the structure of plasma-deposited fluorinated silicon oxide films
(2006-02-24)
Wu, J
;
Wang, YL
;
Kuo, CT
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Fluorine-doped silicon oxide (SiOF) films prepared by plasma enhanced chemical vapor deposition would generate precipitates on the film surface during exposure to air. The chemical and structural changes of SiOF films during the precipitation process were investigated under various fluorine-doping concentrations in SiOF films. Film composition depth profiles characterized by secondary ion mass spectrometer (SIMS) indicate uneven fluorine distribution within SiOF film after precipitation. During the precipitation process, the Fourier transform infrared (FTIR) spectra of SiOF films showed the decreasing trend in the intensities of Si-F-n (n = 1, 2...) bonding peak, whereas an opposing trend in Si-OH bonding as well as the shoulder peak of Si-O stretching mode were observed. Moreover, the formation of the precipitates lead to lower refractive index, a relief in compressive residual stress, and higher wet etch rate of SiOF films. The structural changes of SiOF films due to the formation of precipitates were extensively discussed. (c) 2005 Elsevier B.V. All rights reserved.
Effects of ammonia plasma treatment on the surface characteristics of carbon fibers
(2006-02-24)
Wen, HC
;
Yang, K
;
Ou, KL
;
Wu, WF
;
Chou, CP
Carbon fibers were grown from cobalt catalysts with larger size (> 100 nm), and the size distribution can be controlled by pretreatment. Pretreated cobalt catalytic-layers were observed as islands, which can enhance the growth of carbon fibers. The carbon fibers were treated by ammonia plasma in a PECVD system. High-energy ammonia plasma not only can cause damage but also adsorb on carbon fibers. The ammonia plasma treatment resulted in the etching effect. It is also observed that the more treatment time, the more disorder in structures of carbon fibers. The N-H functional groups were found on the surfaces of ammonia plasma treated carbon fibers and this observation can be further investigated to develop chemical sensor application. (c) 2005 Elsevier B.V. All rights reserved.
Synthesis and characteristics of polyimide/siloxane hybrid films for reliability adhesion
(2006-02-24)
Tsai, MH
;
Chiang, PC
;
Whang, WT
;
Ko, CJ
;
Huang, SL
Polyimide/siloxane (PISi) hybrid films from 2,2'-bis[4-(3-aminodiphenoxy)phenyl]sulfone (in-BAPS), 3,3'-oxydiphthatic anhydride (ODPA) and p-aminopropyltrimethoxysilane (APrTS) have been successfully fabricated by an in-situ sol-gel process. The APrTS is used to introduce siloxane structure and to be the end-capped agent to control the polymer block chain length in the range of 5000-20000 g/mol. The network structure of the PISi hybrid film is formed through the hydrolysis and condensation reactions. The PISi hybrid films with various polyimide block chain lengths are characterized with regard to the structure effect, mechanical properties, adhesion strength, adhesive melting flow and thermal stability. The result indicates that the more APrTS is contained, the shorter of the polyimide block chain length is formed and thus the lower inherent viscosity of APrTS-PAA is obtained. It is also suggested that the cross-linked density of the PISi hybrid film increases with the increase in the amount of APrTS. The network structure of the hybrid film reinforces the pure PI and makes the coefficient of thermal expansion (CTE) as well as adhesive melting flow decrease. Based on the dynamic mechanical analyses (DMA), the hybrid film with higher cross-linked density possesses superior mechanical property at elevated temperature. In addition, the introduction of APrTS causes an increase in thermal stability due to the network structure of hybrid film and the filler effect of the siloxane. (c) 2005 Elsevier B.V. All rights reserved.
The 3rd Asian Conference on Chemical Vapor Deposition (3rd Asian-CVD), Taipei, Taiwan, November 12-14, 2004 - Preface
(2006-02-24)
Feng, ZC
;
Chen, CF
;
Kuo, CT
;
Williams, K
;
Shan, W
Heat, moisture and chemical resistance on low dielectric constant (low-k) film using diethoxymethylsilane (DEMS) prepared by plasma enhanced chemical vapor deposition
(2006-02-24)
Cheng, YL
;
Wang, YL
;
Lan, JK
;
Hwang, GJ
;
O'Neil, ML
Resistance of low dielectric constant (low-k) dielectrics, deposited using Diethoxymethylsilane (DEMS) precursor and helium (He) carrier gas with or without oxygen (O-2) reaction gas, against heat, moisture stress and chemical treatment is clarified. The low dielectric constant organosilicate glass (OSG) films deposited using DEMS and O-2 is shown to be the most reliable: the dielectric constant are stable even after a heating test at 700 degrees C and a pressure cooker test (PCT) for 168 h. This stability is high enough to ensure the low-k properties throughout fabricating multilevel interconnects and long-term reliability after the fabrication. This is due to the stability of Si-CH3 bonds and more Si-C-Si- bonds, which has high degree of cross-linking. However, the degradation of the dielectric constant occurs after O-2 plasma ashing process. The nitrogen plasma treatment is proposed to prevent the damage from O-2 attack in the low-k films deposited using DEMS precursor. (c) 2005 Elsevier B.V. All rights reserved.
F-VEP AND ALPHA-SUPPRESSED EEG-PHYSIOLOGICAL EVIDENCE OF INNER-LIGHT PERCEPTION DURING ZEN MEDITATION
(2006-02-25)
Chang, Kang-Ming
;
Lo, Pei-Chen
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper firstly reports the visual response to the inner light (a form of qi) and the outside stimulus during Zen meditation. It has been reported literally that inner light perception is the common experience for prayers or Zen-meditation practitioners. In this paper, we propose a method to quantify the EEG (electroencephalograph) and F-VEP (flash visual evoked potential) that characterize this experience. Based on wavelet analysis, we derived a set of parameters that effectively signify the alpha-suppressed EEG pattern. Furthermore, this paper presents our new results of analyzing the F-VEP data, mainly the peak amplitude. The observation of little variation in amplitude during Zen meditation reflects a more stable visual perceptive system during Zen meditation that is contrary to the visual response of the control subjects under eye-closed relaxation.
An ultra-low-power image compressor for capsule endoscope
(2006-02-25)
Lin, Meng-Chun
;
Dung, Lan-Rong
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Weng, Ping-Kuo
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電控工程研究所
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Institute of Electrical and Control Engineering
Background: Gastrointestinal (GI) endoscopy has been popularly applied for the diagnosis of diseases of the alimentary canal including Crohn's Disease, Celiac disease and other malabsorption disorders, benign and malignant tumors of the small intestine, vascular disorders and medication related small bowel injury. The wireless capsule endoscope has been successfully utilized to diagnose diseases of the small intestine and alleviate the discomfort and pain of patients. However, the resolution of demosaicked image is still low, and some interesting spots may be unintentionally omitted. Especially, the images will be severely distorted when physicians zoom images in for detailed diagnosis. Increasing resolution may cause significant power consumption in RF transmitter; hence, image compression is necessary for saving the power dissipation of RF transmitter. To overcome this drawback, we have been developing a new capsule endoscope, called GICam. Methods: We developed an ultra-low-power image compression processor for capsule endoscope or swallowable imaging capsules. In applications of capsule endoscopy, it is imperative to consider battery life/performance trade-offs. Applying state-of-the-art video compression techniques may significantly reduce the image bit rate by their high compression ratio, but they all require intensive computation and consume much battery power. There are many fast compression algorithms for reducing computation load; however, they may result in distortion of the original image, which is not good for use in the medical care. Thus, this paper will first simplify traditional video compression algorithms and propose a scalable compression architecture. Conclusion: As the result, the developed video compressor only costs 31 K gates at 2 frames per second, consumes 14.92 mW, and reduces the video size by 75% at least.
Formation of nanostructures of hexaphenylsilole with enhanced color-tunable emissions
(2006-02-26)
Bhongale, CJ
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Chang, CW
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Diau, EWG
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Hsu, CS
;
Dong, YQ
Nanostructures of 1,1,2,3,4,5-hexaphenylsilole (HPS) of various types were obtained on simple reprecipitation with THF as solvent and water as non-solvent. The formation and evolution of these nanostructures were monitored with scanning electron microscopy. Using picosecond time-correlated single-photon counting, we observed enhanced emission and fluorescence lifetimes at volume fractions 70-90% of added water. We report the first enhanced color-tunable emissions of a conjugated organic compound (HPS) due to the formation of nanoflowers, nanoglobules and microglobules, and provide time scales for those nanostructures and the corresponding intermolecular interactions in the aggregates. (c) 2005 Elsevier B.V. All rights reserved.
Complementary carbon nanotube-gated carbon nanotube thin-film transistor
(2006-02-27)
Chen, BH
;
Lin, HC
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Huang, TY
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Wei, JH
;
Wang, HH
We introduce, a complementary carbon nanotube (CNT)-gated CNT thin-film field effect transistor (FET). By using two perpendicularly crossed single-wall CNT (SWNT) bundles as the gate and the channel interchangeably, a sub-50 nm complementary CNT-FET is demonstrated. It is found that the new CNT-FET shows acceptable FET characteristics by interchanging the roles of the gate and the channel. The unique dual functionality of the device will open up a new possibility and flexibility in the design of future complementary CNT electronic circuits. (c) 2006 American Institute of Physics.
Molecular dynamics simulation of the enhancement of cobra cardiotoxin and E6 protein binding on mixed self-assembled monolayer molecules
(2006-02-28)
Hung, SW
;
Hwang, JK
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Tseng, F
;
Chang, JM
;
Chen, CC
Molecular dynamics simulations are performed on n-alkinethiol self-assembled monolayers (SAMs) and their mixture on a gold surface so that the orientations of the binding of cobra cardiotoxin and E6 protein molecules can be selected using the mixing, ratio of CH3-terminated SAMs with different chain lengths. The simulations suggest that a SAM surface with different mixing ratios may provide a possible platform for aligning protein molecules with a desired orientation and for enhancing the binding energy of the protein on the designed surface.
New analytical solutions for groundwater flow in wedge-shaped aquifers with various topographic boundary conditions
(2006-03-01)
Yeh, HD
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Chang, YC
;
環境工程研究所
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Institute of Environmental Engineering
The hydraulic head distribution in a wedge-shaped aquifer depends on the wedge angle and the topographic and hydrogeological boundary conditions. In addition, an equation in terms of the radial distance with trigonometric functions along the boundary may be suitable to describe the water level configuration for a valley flank with a gentle sloping and rolling topography. This paper develops a general mathematical model including the governing equation and a variety of boundary conditions for the groundwater flow within a wedge-shaped aquifer. Based on the model, a new closed-form solution for transient flow in the wedge-shaped aquifer is derived via the finite sine transform and Hankel transform. In addition, a numerical approach, including the roots search scheme, the Gaussian quadrature, and Shanks' method, is proposed for efficiently evaluating the infinite series and the infinite integral presented in the solution. This solution may be used to describe the head distribution for wedges that image theory is inapplicable, and to explore the effects of the recharge from various topographic boundaries on the groundwater flow system within a wedge-shaped aquifer. (c) 2005 Elsevier Ltd. All rights reserved.
Optical beams in sub-strongly non-local nonlinear media: A variational solution
(2006-03-01)
Guo, Q
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Luo, B
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Chi, S
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光電工程學系
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Department of Photonics
Discussed is the propagation of optical beams in non-local nonlinear media modelled by 1 + 1D non-local nonlinear Schrodinger equation (NNLSE). In the sub-strongly non-local case, an approximate analytical solution is obtained for an arbitrary response function by a variational approach. Described by a combination of the Jacobian elliptic functions, the solution is periodic, and its period depends on not only the input power but also the initial beam width, which is confirmed by the numerical simulation of the NNLSE. (c) 2005 Elsevier B.V. All rights reserved.