Browsing by Issue Date, starting with "2004-07-01"

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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.
Suppressing opposite-direction interference in TDD/CDMA systems with asymmetric traffic by antenna beamforming
(2004-07-01)
Chen, CJ
;
Wang, LC
;
交大名義發表
;
National Chiao Tung University
One of the key advantages for the time-division duplex (TDD) system is the capability to deliver asymmetric traffic services by allocating different numbers of uplink and downlink time slots. However, in a TDD/code-division multiple-access (CDMA) system, asymmetric traffic may result in severe opposite-direction interference because downlink transmitted signals from neighboring base stations may interfere with the uplink received signals of the home cell. In this paper, we investigate the effect of four-antenna beamforming schemes from the perspective of suppressing the opposite-direction interference. We compare the uplink bit energy-to-interference density ratio of a traditional beam-steering technique (Scheme 1) with that of the minimum-variance distortionless-response (MVDR) beamformer (Scheme 11). Furthermore, Scheme III applies the conventional beam-steering technique for both downlink transmissions and the uplink reception. In Scheme IV, we implement beam-steering for downlink transmissions, while adopting the MVDR beamformer to process the uplink signals received at base stations. Our numerical results indicate that Scheme IV outperforms all the other three schemes, which can effectively suppress the strong opposite-direction interference in TDD/CDMA systems. While keeping low implementation costs in mind, employing the simpler Scheme HI in a sectorized cellular system can also allow every cell to provide different rates of asymmetric traffic services.
Diode-pumped Q-switched laser with intracavity sum frequency mixing in periodically poled KTP
(2004-07-01)
Chen, YF
;
Chen, YS
;
Tsai, SW
;
電子物理學系
;
光電工程學系
We report on a diode pumped Q-switched yellow-orange laser, with intracavity sum-frequency generation, in a periodically poled KTiOPO4 crystal in a diode-pumped Q-switched dual-wavelength laser at 1064 and 1342 nm. The conversion efficiency is measured as a function of crystal temperature, incident pump power, and pulse repetition rate. Under optimal phase-matching conditions, the highest yellow-orange average power was 610 mW at a pump power of 17 W.
Improved subthreshold slope method for precise extraction of gate capacitive coupling coefficients in stacked gate and source-side injection flash memory cells
(2004-07-01)
Cho, CYS
;
Chen, MJ
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Existing subthreshold slope methods are shown to be far from accurate in extracting gate capacitive coupling coefficient alpha(G) in stacked gate flash memory cells. The origin of the error is systematically identified: (i) process variations induced mismatch and (ii) underlying bulk capacitive coupling. To alleviate such drawbacks, a new version of the subthreshold slope method at room temperature is established: alpha(G) = 0.06(n(f) - alpha(B))/s(f), where the subthreshold swing s(f) is from flash memory cells, the subthreshold slope factor nf is from dummy transistors via threshold voltage against source-to-substrate bias measurement, and the bulk coupling coefficient alpha(B) is from a linear extension of the dimensional dependencies in the literature. The resulting alpha(G) of around 0.55 again agrees consistently with those dependencies and once drain and source coupling experiment is performed, the relation of Sigma alpha(i) approximate to 1 is achieved for all involved coupling coefficients alpha(i)'s.. The sidewall source-side injection flash memory cells are also investigated. With the improved method, this manufacturing process is proved free of process variations issue and is characterized with alpha(G) of 0.374 and fringing capacitance of 0.204 fF. (C) 2004 Elsevier Ltd. All rights reserved.
A simple Dufort-Frankel-type scheme for the Gross-Pitaevskii equation of Bose-Einstein condensates on different geometries
(2004-07-01)
Lai, MC
;
Huang, CY
;
Lin, TS
;
應用數學系
;
Department of Applied Mathematics
We develop a simple Dufort-Frankel-type scheme for solving the time-dependent Gross-Pitaevskii equation (GPE). The GPE is a nonlinear Schrodinger equation describing the Bose-Einstein condensation (BEC) at very low temperature. Three different geometries including 1D spherically symmetric, 2D cylindrically symmetric, and 3D anisotropic Cartesian domains are considered. The present finite difference method is explicit, linearly unconditional stable and is able to handle the coordinate singularities in a natural way. Furthermore, the scheme is time reversible and satisfies a discrete analogue of density conservation law. (C) 2004 Wiley Periodicals, Inc.