Browsing by Issue Date, starting with "2004-06-24"

Now showing 1 - 20 of 69940

Manufacturing method and apparatus of fiber coupler
(2004-06-24)
Sien, Chi
;
Shiao-Min, Tseng
;
Nan-Kuang, Chen
A manufacturing apparatus and method of a fiber coupler is provided. A movable electric arc is employed to fuse more than two stacked fibers for manufacturing a fiber coupler having a small size and good environment stability. It is advantageous that the fiber coupler can be used in a SDH (Synchronous Digital Hierarchy) communication system, and the method also be used to manufacture the all-fiber CWDM (Coarse Wavelength Division Multiplexing) multiplexer which covers the E-band wavelengths and the sub-components of the OADM (Optical Add/Drop Multiplexer). And, all these functions are difficult to be achieved by the conventional techniques.
Ultrabroadband terahertz field detection by proton-bombarded InP photoconductive antennas
(2004-06-28)
Liu, TA
;
Tani, M
;
Nakajima, M
;
Hangyo, M
;
Sakai, K
Photoconductive ( PC) antennas fabricated on InP bombarded with 180 keV protons of different dosages (InP:H+) all exhibit a useful bandwidth of about 30 THz, comparable to that of the LT-GaAs PC antenna. The peak signal current of the best InP: H+ device (dosage of 10(15) ions/cm(2)) is slightly higher than that of the LT-GaAs one, while the signal-to-noise ratio (SNR) of the former is about half of that of the latter due to lower resistivity. This suggests that InP: H+ can be a good substrate for THz PC antennas with proper annealing and/or implantation recipe. (C) 2004 Optical Society of America.
Sensitivity of complete bandgaps to the shift of movable dielectric rod in two-dimensional photonic crystals with complex lattices
(2004-06-30)
Liu, WL
;
Yang, TJ
;
Gu, BY
;
電子物理學系
;
Department of Electrophysics
Two-dimensional tunable photonic crystals (TPCs) with movable components are proposed, which consist of a circular dielectric rod inserted into a square lattice of square dielectric cylinders in air. The band gap structures of TPCs can be tuned by adjusting the shift of the position of the circular rod in each unit cell. Band gap structures are calculated with the use of the plane-wave expansion method for various structural parameters, such as different filling fractions, ratio of the radius of the circular rod to the side-length of the square cylinder, different shifts or shifting orientations of the circular rod, etc. We find that there is a region of parameters in which the ratio of the gap width to the midgap is insensitive to the shift of the position of the circular dielectric rod. It is anticipated that the proposed TPC may become a favourable candidate of PCs owing to the benefit of facilitating fabrication, allowing a large tolerance.
The growth morphology and crystallinity of electroless NiP deposition on silicon
(2004-06-30)
Tsai, TK
;
Chao, CG
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The growth morphology and crystallinity of the electroless NiP deposited on Si substrate pretreated by SnCl(2)/HCl and PdCl(2)/ HCl solutions is studied using transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), and energy dispersive X-ray spectrum (EDS). Combining cross-sectional and surface observations show that the reaction mechanism of electroless NiP on Si is an electrochemical mechanism and the deposits are composed of a columnar structure grown along the vertical direction of the substrate surface. The phosphorus content does not have influence on the growth morphology but affects the crystallinity of the deposits. The crystallinity of the deposits is directly observed by the lattice image using high-resolution transmission electron microscope (HRTEM). The as-deposited NiP with 10.7 at.% P possesses good crystallinity and consists of Ni nanocrystal about 4-8 nm distributed randomly in the deposits. The size of nanocrystal in the deposits with 15.2 at.% P is about 2-5 nm. The deposits with 20.3 at.% P have a smaller order range and the size of nanocrystal is under 1.5 nm. The grain size decreases as the phosphorus content increases. (C) 2004 Elsevier B.V. All rights reserved.
Electromigration and integration aspects for the copper-SiLK system
(2004-07-01)
Tseng, HS
;
Chiou, BS
;
Wu, WF
;
Ho, CC
;
電子工程學系及電子研究所
In this study, the thermal characteristics and electromigration (EM) resistance of two dielectrics, SiLK(TM) and SiO2, are investigated to evaluate the feasibility of low dielectric-constant SiLK for intermetal. dielectric applications. Liftoff patterning was employed to fabricate the Cu interconnect for the EM test, and the Taguchi method was used in the experimental design to identify the key parameters for a successful liftoff. It was shown that the thermal impedance of the metal lines passivated with SiLK is 14% higher than that of metal lines passivated with SiO2. On the basis of the thermal impedance and temperature rise of the interconnect, it was concluded that the major heat transfer path is via the underlayer dielectric to the Si substrate. The activation energy of EM for Cu passivated with SiLK is smaller, and the EM lifetime is shorter than that of Cu passivated with SiO2. Possible mechanisms are discussed.
Formation of semiconductor quantum rings using GaAs/AlAs partially capped layers
(2004-07-01)
Lee, BC
;
Lee, CP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new method for fabricating semiconductor quantum rings has been developed. Instead of using the conventional GaAs cap layer, we used the GaAs/AlAs cap layer for the ring formation. The additional AlAs layer impedes the inward diffusion of the Ga and Al atoms and results in nicely formed ring structures with a more relaxed growth condition. Because of this layer, the ring-shaped structure can be maintained with a higher annealing temperature without being washed out by the intermixing of Ga/Al with In in the central region of the dots. The shape and the strain distribution of quantum rings have also been characterized by transmission electron microscopy.
Suppression of buoyancy-driven vortex flow resulting from a low speed jet impinging onto a heated disk in a vertical cylinder by cylinder top tilting
(2004-07-01)
Hsieh, JC
;
Cheng, CW
;
Lin, TF
;
機械工程學系
;
Department of Mechanical Engineering
Buoyancy-driven vortex flow resulting from a low speed round gas jet impinging vertically downwards onto a heated horizontal circular disk confined in an adiabatic vertical cylindrical chamber can be strong and even unstable as the buoyancy-to-inertia ratio exceeds certain critical level. An experiment combining flow visualization and temperature measurement is conducted in the present study to explore the suppression of the above buoyancy-driven vortex gas flow by inclining the top of the cylindrical chamber. The chamber top is chosen to incline linearly in the radial direction so that the mean flow in the wall-jet region is accelerated and meanwhile the effective buoyancy signified by the local Rayleigh number reduces in that direction. Specifically, in the present experiment. the disk-to-chamber top separation distance decreases from 20.0 mm at the jet axis to 10.0 mm at the chamber side. Tests are conducted for the jet flow rate varied from 1.0 to 5.0 slpm (standard liter per minute) and the jet-to-disk temperature difference varied from 0 to 35.0 degreesC for two injection pipes with diameter 10.0 and 22.1 mm for the chambers with horizontal and inclined tops. The results from the flow visualization indicate that the chamber top inclination can effectively suppress the unstable buoyancy-induced vortex roll and the temporal flow oscillation at high buoyancy-to-inertia ratios. However, the effects of the chamber top inclination on the inertia-driven rolls are much milder. The non-monotonic air temperature distribution in the radial direction is found to result from the unique vortex flow structure in the chamber. A universal criterion based on the local flow and thermal conditions in the wall-jet region for the onset of the buoyancy-driven roll is proposed. To quantify the characteristics of the vortex flow in the chamber with the inclined top, empirical correlations have been proposed for the size and location of the vortex rolls. (C) 2004 Elsevier Ltd. All rights reserved.
Memory properties of metal/ferroelectric/semiconductor and metal/ferroelectric/insulator/semiconductor structures using rf sputtered ferroelectric Sr0.8Bi2.5Ta1.2Nb0.8O9 thin films
(2004-07-01)
Huang, CH
;
Wang, YK
;
Lue, HT
;
Huang, JY
;
Lee, MZ
Off-axis rf magnetron sputtering has been employed to grow Sr0.8Bi2.5Ta1.2Nb0.8O9 (SBTN) ferroelectric thin films with (115) preferred orientation on SiO2/Si and Si substrates. The lower temperature and the higher oxygen mixing ratios [OMR, O-2/ (Ar+O-2)] used in film processing lead to reduction in the leakage current densities and widening the memory window of the resultant metal-ferroelectric-insulator semiconductor (MRS) structures. The maximum memory windows of the MFIS structures based on 40% OMR SBTN films deposited at 500 degreesC on SiO2/Si substrate are 2.87 and 2.27 V at the bias amplitudes of 10 and 8 V, respectively. With increasing applied voltage, the memory window also increases. The memory window decreases from 2.27 to 1.59 V after the 10(11) switching cycles at a bias amplitude of 8 V. The capacitance difference, DeltaC, between the two states decreases by 48% after retention time of 7000 s. (C) 2003 Elsevier Ltd. All rights reserved.
Fuzzy optimization techniques applied to the design of a digital PMSM servo drive
(2004-07-01)
Cheng, KY
;
Tzou, YY
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a novel design approach by applying gradient optimization with fuzzy step-sizing techniques to the design of a digital permanent magnet synchronous motor (PNSM) servo drive. The servo specifications and design variables are specified and analyzed to formulate a controller optimization problem. The servo responses are then fed back to evaluate the overall system performances, which can be expressed as objective functions with respect to the servo control parameters. According to the objective functions and design specifications, the servo control parameters can be properly tuned toward their optimal values by using the proposed optimization techniques. In order to improve the convergent rate of the optimization process, a fuzzy-logic based step-size tuning strategy is presented. Because of the nonlinear property of the digital servo drives, the tuned servo control parameters may be only optimal for a particular operating point, therefore, once the optimum design is achieved, the proposed fuzzy optimizing controller can perform as an intelligent tuner for on-line gain adaptation under different loading conditions. The proposed fuzzy optimization servo tuner has been realized under a PC-MATLAB-based environment with an on-line controlled digital PMSM servo drive. Simulation and experimental results indicate that the control parameters of a digital PMSM servo drive can be optimized for its dynamic responses under various load conditions.
控制包覆磁性材料之碳基奈米結構製程
(2004-07-01)
郭正次
;
林兆焄
;
駱安亞
;
駱伯遠
本發明係一種控制包覆磁性材料之碳基奈米結構製程，係以電子迴旋共振微波電漿沉積法(化學氣相沉積法)，成長包覆磁性材料之碳奈米結構及其後處理時，施以適當的磁場以改進磁性異向性；並以表面具有觸媒和添加物之基材通以直流偏壓源及加熱，做電漿前處理使進行基材表面蝕刻，再使反應氣體進行化學氣相沉積；藉此，達到控制奈米結構材料之尺寸、形狀、形成具方向性排列成長之奈米結構，可有效提高磁記憶媒體之紀錄密度，並具保護隔離效果以避免相互干擾，而且具磁異方性和矯頑磁力高的效果。
陽明歷史照片巡禮
(國立陽明大學, 2004-07-01)
陽明電子報編輯小組
發黃的照片是否可以讓你陷入時間的隧道中？在這時光隧道中是否勾起你想念的人物、想念的事情？在這初春的時節，電子報於本期起將分次把得來不易的百來張珍貴校園照片逐一向大家介紹，希望隨著這些圖像的重現，再次將大夥的情感凝聚起來！
徵稿公告
(國立陽明大學, 2004-07-01)
陽明電子報編輯小組
一、彰化師範大學「２００４彰化研究學術研討會」徵稿截稿日期：九十三年七月十日相關網址：http://ge03w.ncue.edu.tw 　　二、國立中正大學「２００４年終身學習國際學術研討會：終身學習與新學習文化」徵稿截稿日期：九十三年八月一日相關網址：http://www.ccunix.ccu.edu.tw/~cyiaace/news.php 三、教育部「２００４台灣網際網路研討會(TANET 2004)」徵稿論文截稿日期－8/8 相關網址：http://www.nttu.edu.tw/TANET2004 　　四、台灣藝術大學「藝術學報」徵稿截稿日期：九十三年八月三十一日相關網址：http://www.ntua.edu.tw 五、台灣藝術大學「藝術論文集刊」徵稿截稿日期：九十三年八月三十一日相關網址：http://www.ntua.edu.tw 六、國立高雄海洋科技大學「二００四年運籌管理研討會」徵稿截稿日期：九十三年九月六日相關網址：http://logmgt.nkimt.edu.tw/tlma/new_s.asp 七、德明技術學院「德明學報」徵稿截稿日期：九十三年九月十五日相關網址：http://www.takming.edu.tw/publish 八、嶺東技術學院「嶺東學報研討會」徵稿截稿日期：九十三年九月三十日與三月三十一日相關網址：http://adc.ltc.edu.tw 九、國立台北護理學院「第一屆生死教育與悲傷輔導學術研討會」徵稿截稿日期：九十三年十月十五日十、國立台北護理學院「第一屆生死教育與悲傷輔導學術研討會」徵稿截稿日期：九十三年十月十五日十一、私立康寧醫護暨管理專科學校「康寧學報」徵稿截稿日期：九十三年十一月三十日相關網址：http://www.knjc.edu.tw/admin/aa/publish/default/htm
Alternating coordinates minimization algorithm for estimating parameters of partial erasure plus transition shift model
(2004-07-01)
Kao, TS
;
Cheng, MH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The identification of model parameters of a high-density recording channel is usually difficult and complicated. In this paper, we successfully apply the alternating coordinates minimization (ACM) algorithm for estimating parameters of a partial erasure plus transition shift model (PETSM). The resulting algorithm turns out to iteratively solve two least square problems and is guaranteed to converge. Furthermore, the obtained model for a nonlinear partial response channel is more accurate than conventional models such that the maximum likelihood (ML) detector has better bit error rate (BER) performance without increasing its realization complexity. Computer simulations show that the ACM algorithm can accurately estimate the model parameters and the BER for the detector is significantly improved especially when the transition shift parameter is large.
Optimal implementation of miniature piezoelectric panel speakers using the Taguchi method and genetic algorithm
(2004-07-01)
Bai, MR
;
Lu, YC
;
機械工程學系
;
Department of Mechanical Engineering
A thin and miniature piezoelectric panel speaker has been developed in this paper. The system is modeled using the energy method in conjunction with the finite element method. The electrical system, mechanical system and acoustic loading are considered in combined fashion. The genetic algorithm (GA) and the Taguchi method are employed to achieve optimal designs with low fundamental frequency and high acoustic output. The designs resulting from the optimization are then implemented and evaluated by experiments. These experiments were carried out on the basis of quantitative and subjective performance measures. The experimental results indicate that the piezoelectric panel speakers are capable of producing comparable acoustic output with significantly less electrical power than the conventional voice-coil panel speakers.
Use of WNX as the diffusion barrier for interconnect copper metallization of InGaP-GaAs HBTs
(2004-07-01)
Chang, SW
;
Chang, EY
;
Lee, CS
;
Chen, KS
;
Tseng, CW
Use of WNX as the diffusion barrier for interconnect copper metallization of InGaP-GaAs heterojunction bipolar transistors (HBTs) was studied. The WNX (40 nm) and Cu (400 nm) films were deposited sequentially on the InGaP-GaAs HBT wafers as the diffusion barrier and interconnect metallization layer, respectively, using the sputtering method. As judged from the data of scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy, and sheet resistance, the Cu-WNX-SiN and Cu-WNX-Au structures were very stable up to 550 degreesC and 400 degreesC annealing, respectively. Current accelerated stress test was conducted on the Cu-WNX metallized HBTs with V-CE = 2 V, J(C) = 140 kA/cm(2) and stressed for 55 h, the current gain (beta) of these HBTs showed no degradation and was still higher than 100 after the stress test. The Cu-WNX metallized HBTs were also thermally annealed at 250 degreesC for 25 h and showed no degradation in the device characteristics after the annealing. For comparison, HBTs with An interconnect metallization were also processed, and these two kinds of devices showed similar characteristics after the stress tests. From these results, it is demonstrated that WNX is a good diffusion barrier for the interconnection copper metallization of GaAs HBTs.
第一屆台灣地區認知神經科學暑期學校網路公告
(國立陽明大學, 2004-07-01)
陽明電子報編輯小組
日期時間：8/16 - 9/3 活　　動：第一屆台灣地區認知神經科學暑期學校地　　點：國立中央大學
Chaos synchronization in a mutually coupled laser array subjected to self-mixing modulation
(2004-07-01)
Kawai, R
;
Lih, JS
;
Ko, JY
;
Chern, JL
;
Otsuka, K
This tutorial presents a detailed description of experiments, simulations, and characterizations of chaos synchronization phenomena in the model of a mutually coupled microchip solid-state laser array subjected to self-mixing feedback modulation. We demonstrate a transition to synchronized chaos by the method of 'phase squeezing' with increasing field overlap between the two lasers. This phenomenon is well reproduced by numerical simulation of model equations. It is also shown that low energy variation as well as high disorder are concurrently established in synchronized chaos in the present system. The deterministic random switching (i.e., chaotic itinerancy) among phase-squeezed states and synchronized chaos states is numerically demonstrated in a transition region from a phase-squeezed state to a synchronized state. We characterize observed behaviours; using such methods as singular value deposition (SVD), joint time-frequency analysis (JTFA) introducing a similarity function, and coarse-grained information transfer rate (CITR) analysis of long-term experimental or numerical time series, and discuss the physical significance of observed nonlinear dynamics in conjunction with chaos synchronization in mutually coupled lasers.
Temperature effect on read current in a two-bit nitride-based trapping storage flash EEPROM cell
(2004-07-01)
Liu, MY
;
Chang, YW
;
Zous, NK
;
Yang, I
;
Lu, TC
The temperature effect on the read current of a two-bit nitride-storage Flash memory cell is investigated. In contrast to a conventional silicon-oxide-nitride-oxide (SONOS) cell with uniform Fowler-Nordheim (FN) programming, a significant high-V-T state read current increase, which results in the read window narrowing at high temperature, is observed in a channel hot electron (CHE) programmed cell. The increment of high-V-T state leakage current shows a positive correlation with program/erase threshold voltage window. Since the temperature effect is very sensitive to a locally trapped charge profile, a two-dimensional simulation with a step charge profile is employed to characterize the relationship between current increment and both charge width and charge density.
A novel potential-based path planning of 3-D articulated robots with moving bases
(2004-07-01)
Lin, CC
;
Pan, CC
;
Chuang, JH
;
資訊工程學系
;
Department of Computer Science
This paper proposes a novel path planning algorithm of 3-D articulated robots with moving bases based on a generalized potential field model. The approach computes, similar to that done in electrostatics, repulsive forces and torques between charged objects. A collision-free path can be obtained by locally adjusting the robot configuration to search for minimum potential configurations using these forces and torques. The proposed approach is efficient since these potential gradients are analytically tractable. In order to speedup the computation, a sequential planning strategy is adopted. Simulation results show that the proposed algorithm works well, in terms of collision avoidance and computation efficiency.
Optimization of post-N-2 treatment and undoped-Si-glass cap to improve metal wring delamination in deep submicron high-density plasma-fluorinated silica glass intermetal dielectric application
(2004-07-01)
Cheng, YL
;
Wang, YL
;
Lan, JK
;
Wu, SA
;
Chang, SC
Integration issues of metal line delamination from fluorinated silica glass (FSG) in deep submicron intermetal dielectric applications were investigated in this study. A metal line peeled off after a nonoptimized in situ deposition of undoped-silicon-glass (USG; SiO2) capping layer followed the post-FSG-chemical mechanical polishing N-2 treatment. It was found that higher bias power and longer process time of N-2 treatment led to more active fluorine species diffusing from the FSG films to the USG surface, which might react with subsequent Ti/TiN/W metal layer and result in metal delamination. Using plasma-enhanced N-2 treatment and ex situ USG capping with lower initial deposition temperature by extra cooling step, the stability of the FSG films was improved and resulted in a robust structure without metal peeling. (C) 2004 American Vacuum Society.