Browsing by Issue Date, starting with "1995-07-15"

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BOUNDARY-STRUCTURE DETERMINATION OF AG/SI(111) INTERFACES BY X-RAY-DIFFRACTION
(1995-07-15)
ABURANO, RD
;
HONG, H
;
ROESLER, JM
;
CHUNG, K
;
LIN, DS
Different Ag/Si(111) systems have been examined using synchrotron x-ray diffraction. Multi-atomic-layer deposition of Ag onto a Si(111)-(7X7) surface maintained at room temperature results in an unstrained, (111)-oriented film. The interface shows a Ag-modified (7X7) structure which when annealed above 200-250 degrees C transforms to a(1X1) structure. Although this is near the characteristic temperature for formation of the (root (3) over bar X root (3) over bar)R30 degrees surface reconstruction commonly observed for a monolayer of Ag adsorbed on Si(111), no evidence of this (root (3) over bar X root (3) over bar)R30 degrees reconstruction was found at the interface, A Ag monolayer (root (3) over bar X root (3) over bar)R30 degrees surface, further covered by multilayer Ag deposition at room temperature, also shows no indication of the (root (3) over bar X root (3) over bar)R30 degrees reconstruction at the interface. This indicates that the actual interface structure may or may not be related to the clean or adsorbed layer structures. The structure of the Ag-Si interface was further characterized by scans of the crystal truncation rods. Both the (7X7) interface prepared by room-temperature deposition and the annealed (1X1) interface show fairly sharp boundaries. The results suggest some intermixing occurs at the monolayer level for the annealed interface. The structure of the Ag film was also investigated.
EPITAXY OF SI1-XGEX BY ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION USING SI2H6 AND GEH4
(1995-07-15)
CHEN, LP
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CHOU, TC
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TSAI, WC
;
HUANG, GW
;
TSENG, HC
Disilane and germane were used to grow Si1-xGex epilayers at 550 degrees C by ultrahigh-vacuum chemical vapor deposition (UHVCVD). The solid composition x and growth rate of Si1-xGex were evaluated from double-crystal X-ray rocking curves and show very strong dependence on the total source gas flow rate ([GeH4]+[Si2H6]) and the gas ratio ([GeH4]/[GeH4]+[Si2H6]). The solid composition increases with increase of the gas ratio and also with increasing the total source flux by keeping gas ratio constant. The growth rate increases with the solid composition at lower values and then becomes saturated in the higher composition range (x>0.22). The results can be explained by the relationships of the source fluxes, relative incorporation efficiency at activated surface sites and hydrogen desorption under different growth conditions.
吾們家裏也有螢火蟲和螞蟻
(1995-07-27)
管管
SCALABLE ARRAY ARCHITECTURE DESIGN FOR FULL SEARCH BLOCK MATCHING
(1995-08-01)
CHANG, SF
;
HWANG, JH
;
JEN, CW
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Block matching is a widely used motion estimation algorithm in current video systems, Among typical searching strategies, the full search scheme provides better precision and regular data flow as well as higher parallelism, a characteristic that is advantageous for VLSI implementation, However, the huge computation load incurred by full search results in high cost, especially in high pixel rate applications, Since block matching algorithm is used in a wide range of pixel rates, an architecture that is cascadable and offers variable computing power is promising, In the first part of this paper, an approach based on dependence graph (DG) is proposed to analyze the operation sequence and data flow of full search block matching. The approach employs a transformation on DG's, called slice and tile, to produce different forms of DG's, Through this technique, most existing architectures can be represented in graphs for analysis, and new architectures can be found, In the second part of this paper, a new architecture is presented that features cascadable modules of processing elements (PE's) with simple interconnection. Therefore, flexibility in computing power is available. The other advantages include variable sizes of the search area and 100% PE utilization, These characteristics offer great flexibility and efficiency for different applications. This architecture is implemented with thirty-two PE's in one chip that consists of 102 K transistors.
A NEW STRUCTURE OF THE 2-D SILICON RETINA
(1995-08-01)
WU, CY
;
CHIU, CF
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new silicon retina is proposed to realize the functions of the vertebrate retina. In the proposed silicon retina, each basic cell consists of two separated bipolar phototransistors only. The smooth function of the horizontal cell in the vertebrate retina is efficiently achieved by the diffusion acid redistribution of the photogenerated excess carriers in the common base region of the phototransistors. Thus, the structure of the new silicon retina is very simple and compact. It can be easily implemented in both CMOS and BiCMOS technologies with a small chip area. A 2-D array of 32 * 32 new silicon retina cells has been designed and fabricated in 0.8 mu m N-well CMOS process, Experimental results show that the new silicon retina is capable of extracting the edge of the image and detecting the moving object.
HOLOGRAM ENHANCEMENT IN PHOTOREFRACTIVE MEDIA
(1995-08-01)
YEH, PC
;
GU, C
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CHENG, CJ
;
HSU, KY
;
光電工程學系
We consider the possibility of restoration and/or enhancement of decaying holograms in photorefractive media by using a simple optical readout in conjunction with a phase conjugator. The results indicate that extremely weak holograms can be enhanced provided that the two-beam coupling is sufficiently strong. Steady-state photorefractive holograms can be maintained continuously without decay by using a properly designed readout scheme. The result also provides an explanation for the formation of mutually pumped phase conjugation in terms of the amplification of initial noise gratings.
THE INFLUENCE OF CULTURE ON INDUSTRIAL BUYING SELECTION CRITERIA IN TAIWAN AND MAINLAND CHINA
(1995-08-01)
CHANG, KC
;
DING, CG
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交大名義發表
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管理科學系
;
National Chiao Tung University
This study investigated the effects of culture on two industrial vendor selection criteria, price and delivery schedule. Hofstede's dimensions and Chinese Culture Connection's Chinese value survey (CVS), two instruments based on different constructs, were used together to represent the cultural characteristics of industrial buyers from Taiwan and Mainland China. The findings indicated that the CVS was more suitable for detecting cultural differences between these two areas and that masculinity, integration, and moral discipline had significant effects on price awards.
A NEW SIMPLIFIED THRESHOLD-VOLTAGE MODEL FOR N-MOSFETS WITH NONUNIFORMLY DOPED SUBSTRATE AND ITS APPLICATION TO MOSFETS MINIATURIZATION
(1995-08-01)
MAA, JJ
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WU, CY
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交大名義發表
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電子工程學系及電子研究所
;
National Chiao Tung University
The formulation, verification, and application of a new simplified 2-D threshold voltage model for n-MOSFET's with nonuniformly doped substrate profile are provided, in which the averaged normal field at the Si/SiO2 interface in the active channel is quoted from a simplified solution of two-dimensional Poisson equation using the Green function technique. Starting with the expression of this average normal field, a simple threshold-voltage model for short-channel n-MOSFET's with nonuniformly doped substrate profile is explicitly expressed in terms of device structures and terminal voltages by considering parabolic source-drain boundary potentials. Moreover, the effects of the junction depth on the threshold voltage are examined in detail. It is shown that the DLBL effect cannot be completely eliminated by simply increasing the substrate doping concentration. Comparisons among developed model, 2-D numerical analysis, and experimental data have been made and the accuracy of the developed analytical model has been verified. In addition, a direct extension of our model to the case of uniformly doped substrates leads to a new constraint equation for device miniaturization.
A UNIFIED APPROACH TO SCRAMBLING FILTER DESIGN
(1995-08-01)
KING, CW
;
LIN, CA
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電控工程研究所
;
Institute of Electrical and Control Engineering
Most speech scrambling systems are either linear periodic filters or can be modeled as such, It is well-known that from an input-output point of view, a periodic filter is equivalent to a multi-input multi-output linear time-invariant system and thus a rational transfer matrix, In this paper, we propose a framework, based on transfer matrices and frequency domain descriptions, for analysis and design of speech scrambling filters, We derive necessary and sufficient conditions for a scrambling system to be insensitive to frame synchronization error, We propose a procedure for the design of scrambling filters that are insensitive to synchronization error and have zero bandwidth expansion. An illustrative design example is given.
SUPPRESSION OF BORON PENETRATION IN BF2-IMPLANTED P-TYPE GATE MOSFET BY TRAPPING OF FLUORINES IN AMORPHOUS GATE
(1995-08-01)
LIN, CY
;
CHANG, CY
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HSU, CCH
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電控工程研究所
;
奈米中心
This work reports the use of amorphous/polysilicon gate electrode in BF2-implanted poly-gated P-MOSFET's to suppress the boron penetration, SIMS analysis clearly illustrates that fluorine prefers to accumulate in the layer of amorphous silicon. The retardation of boron diffusion is therefore achieved by the trapping of fluorine in the amorphous layer of stacked amorphous/polysilicon (SAP) p-type gate due to a lower diffusion rate of fluorine in the amorphous silicon layer. Polysilicon depletion effect did not become more severe by introducing the amorphous silicon. In addition, gate oxide reliability is not degraded by using this gate structure. Results show that the structure is a promising gate electrode for future dual-poly gate CMOS technology development.
PROPAGATION OF LOWER-ORDER MODES IN A RADIALLY ANISOTROPIC CYLINDRICAL WAVE-GUIDE WITH LIQUID-CRYSTAL CLADDING
(1995-08-01)
CHEN, TJ
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CHEN, SH
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交大名義發表
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光電工程學系
;
National Chiao Tung University
The propagation behavior of the four lower-order modes, HE(11), TE(01), TM(01), and HE(21), in a radially anisotropic cylindrical waveguide with liquid crystal cladding is studied both theoretically and experimentally. The cylindrical waveguide is a doubly-clad fiber with an isotropic core and inner cladding and a radially anisotropic outer cladding made of nematic liquid crystal. Theoretically, the propagation and decay constants for the TE(01) and TM(01) modes are obtained by solving the wave equations exactly, while those for the HE(11) and HE(21) modes are derived using perturbation techniques under the weakly guiding approximation. It is predicted that in such a structure the guided TE(01) mode can be separated from the leaky HE(11), TM(01), and HE(21) modes. The theoretical results show good agreement with the experimental observations for a 3 cm long fiber cell with a 5 mu m inner cladding radius.
A NEW RESCHEDULING METHOD FOR COMPUTER-BASED SCHEDULING SYSTEMS
(1995-08-01)
WU, HH
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LI, RK
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工業工程與管理學系
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Department of Industrial Engineering and Management
Providing a powerful interactive tool for the scheduler to quickly and easily react to the inevitable rescheduling changes is mandatory in today's complex and flexible manufacturing environment. The conventional approaches either employ the regeneration method, which results in unsatisfactory response times, or use methods that require too much manual intervention for editing operations to be changed. A new rescheduling method is proposed in this paper which addresses these problems. The fundamental scheme of this rescheduling method is based on a scheduling graph as well as concepts of time effect and relationship effect. The scheduling graph is an alternative representation structure of a schedule Gantt chart. The time effect and relationship effect provide functions of (1) identifying those operations that require revision, (2) revising those identified affected operations (via a partial change of the scheduling graph structure) and (3) updating starting and ending times of those revised operations. The rescheduling method both reduces manual intervention of rescheduling to a minimum and permits net change (opposite to regeneration) rescheduling to be achievable. This rescheduling method can be embedded in current computer assistance scheduling systems so as to enhance their effectiveness.
METALLURGICAL REACTIONS AT THE INTERFACE OF SN/PB SOLDER AND ELECTROLESS COPPER-PLATED ALN SUBSTRATE
(1995-08-01)
CHIOU, BS
;
CHANG, JH
;
DUH, JG
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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
Intermetallic formation between electroless-plated copper and Sn/Pb solder is investigated. An interlayer is formed between copper and solder, and segregation of Pb-rich and Sn-rich phases are observed. X-ray diffraction and EDX analysis results suggest that the major intermetallic formed in the interlayer is Cu6Sn5. For the as-plated sample, the adhesion strength of Cu to the AIN substrate after 150 degrees C aging is affected by both the recrystallization and the creep of copper. For the soldered specimen, the presence of intermetallic compound causes cracks to propagate along the intermetallic/Cu interface and results in a decrease of the adhesion strength.
THE TRANSFORM IMAGE CODEC BASED ON FUZZY CONTROL AND HUMAN VISUAL-SYSTEM
(1995-08-01)
WEN, KA
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LU, CY
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TSAI, MC
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交大名義發表
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電子工程學系及電子研究所
A novel processing scheme for gray level image compression based on the human visual system (HVS) and fuzzy control is proposed. The spatial model of the threshold vision that incorporates the masking processes takes account of two major sensitivities of the human visual system, namely background illumination levels and spatial frequency sensitivities. The distortion measures use common sense fuzzy rules for image quality prediction. The human visual models have been successfully applied in image compression. By the addition of the visual model, performance of these systems have a visible improvement of subject quality depending on visual perception. The processed image performs both improved compression ratio as well as improved SNR (signal to noise ratio) in compression to the standardized still image compression technique, i.e., the JPEG.
SYNTHESIS OF CARBON NITRIDE FILMS BY MAGNETICALLY ROTATED ARC-PLASMA JET CHEMICAL-VAPOR-DEPOSITION
(1995-08-01)
YEN, TY
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CHOU, CP
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交大名義發表
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機械工程學系
;
National Chiao Tung University
Carbon Nitride films have been grown on nickel substrates by magnetically rotated arc-plasma jet chemical vapor deposition (CVD). These films were characterized by scanning electron microscopy (SEM), wavelength dispersive X-ray spectrometry (WDS) transmission electron microscopy (TEM), and Raman spectroscopy. Small grains (similar to 0.1 mu m) as well as nanocrystallites found in the films were identified to be beta-C3N4. Raman spectrum also confirmed the existence of beta-C3N4 phase in the films through three pronounced Raman bands at low frequency as expected from the Hooke's law approximation.
A LOW-COST RASTER ENGINE FOR VIDEO GAME, MULTIMEDIA PC AND INTERACTIVE TV
(1995-08-01)
CHEN, CL
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LIANG, BS
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JEN, CW
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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 low-cost Raster Engine (RE) is designed and implemented to improve the performance of 3D computer graphics and image composition application for video games, multimedia PCs and interactive TVs. Three operation modes: Gouraud and Phong shading algorithms, and image composition are incorporated in this chip. Modified digital differential analyzer (DDA), 2-level pipeline, and constant execution time for calculating cos(n) theta are proposed as the features of this design. The accelerator is implemented by 0.8 um SPDM CMOS VLSI technology and able to release more then 50% CPU loads.
ERROR PROPERTIES OF STADIA MEASUREMENTS WITH INCOMPLETE INTERCEPT
(1995-08-01)
SHIH, TY
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交大名義發表
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土木工程學系
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National Chiao Tung University
;
Department of Civil Engineering
The error properties of the stadia measurement with incomplete-intercept readings were analyzed in this study. Several numerical experiments were also conducted. Finally a comparison was made on the magnitude of the stochastic error propagated with the error introduced via the nonrigorous functional model for incomplete-intercept readings. This comparison has provided an opportunity to compare the significance of functional-error with stochastic-error components. The identified functional error can be easily removed; meanwhile, the stochastic-error component of measurement is valuable for the documentation of surveying quality.
ON THE LOOK-AHEAD PROBLEM IN LEXICAL ANALYSIS
(1995-08-01)
YANG, W
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交大名義發表
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資訊工程學系
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National Chiao Tung University
;
Department of Computer Science
Modern programming languages use regular expressions to define valid tokens, Traditional lexical analyzers based on minimum deterministic finite automata for regular expressions cannot handle the look-ahead problem. The scanner writer needs to explicitly identify the look-ahead states and code the buffering and re-scanning operations by hand. We identify the class of finite look-ahead finite automata, which is general enough to include all finite automata of practical lexical analyzers, Finite look-ahead finite automata are then transformed into suffix finite automata. A new lexical analyzer makes use of the suffix finite automata to identify tokens. The new lexical analyzer solves the look-ahead problem in a table-driven approach and it can detect lexical errors at an earlier time than traditional lexical analyzers. The extra cost of the new lexical analyzers is the larger state transition table and three additional 1-dimensional tables. Incremental lexical analysis is also discussed.
ACCURATE QUASI-TEM SPECTRAL-DOMAIN ANALYSIS OF SINGLE AND MULTIPLE COUPLED MICROSTRIP LINES OF ARBITRARY METALLIZATION THICKNESS
(1995-08-01)
KUO, JT
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交大名義發表
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電信工程研究所
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National Chiao Tung University
;
Institute of Communications Engineering
The quasi-TEM spectral domain approach (SDA) is extended to rigorously and efficiently analyze single and multiple coupled microstrip lines of arbitrary metallization thickness, The charge distributions on both the horizontal and vertical conductor surfaces are modeled by global basis functions, This results in a relatively small matrix for accurate determination of the line parameters of coupled thick microstrips. A convergence study is performed for the results of a pair of coupled lines with crucial structural parameters to explore the conditions for obtaining reliable solutions using the technique. Results for thick microstrips are validated through comparison with those from available measurements and another theoretical technique. The soundness of the technique is further demonstrated by looking into the trend of the results obtained by a simplified model in which the structural parameters are pushed, step by step, to the numerical extremities. Variations of circuit parameters of a four-line coupled microstrip structure due to the change of finite metallization thickness are presented and discussed.
IMPLEMENTATION OF DAMPED RESOLVED ACCELERATION CONTROL FOR A MANIPULATOR NEAR SINGULARITY
(1995-08-01)
LIN, SK
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WU, SL
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交大名義發表
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電控工程研究所
;
National Chiao Tung University
Resolved acceleration control fails in the neighbourhood of the singularity of the Jacobian matrix. The damped least-squares method has been proposed to overcome this singularity problem. In earlier work, all components of the velocity of the end-effector were damped when a manipulator was near a singular point, so that some components of the velocity that are physically feasible were also damped, sacrificing accuracy. This paper presents a new approach that applies the damped least-squares method only to the degenerated directions since only the components of the velocity in the degenerated directions are inherently impossible to generate. This approach requires few computations and then can be implemented in real-time. Another feature is that the selection of the damping factor is a one-dimensional problem. The new damped resolved acceleration control scheme is implemented on the Puma 560 robot. The experiment results show the validity and the drawbacks of the damped resolved acceleration control in the neighbourhood of singular points.