Browsing by Issue Date, starting with "1993-09-06"

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GROWTH OF UNDOPED POLYCRYSTALLINE SI BY AN ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION SYSTEM
(1993-09-06)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
Deposition of undoped polycrystalline-silicon (poly-Si) films on SiO2 using an ultrahigh vacuum chemical vapor deposition system was investigated. Poly-Si films with high crystallinity were obtained at a temperature as low as 525-degrees-C. The layer growth process was found to proceed with an activation energy of 44 +/- 2 kcal/mol, and is dominated by the desorption rate of surface-bonded hydrogen atoms. An incubation time was observed prior to the film deposition. This incubation period increased with decreasing growth temperature, resulting from slower nucleation and growth rates ai lower temperatures.
ANOMALOUS DOPING BEHAVIOR OF IN-SITU BORON-DOPED POLYCRYSTALLINE SILICON DEPOSITED BY ULTRAHIGH-VACUUM CHEMICAL-VAPOR-DEPOSITION
(1993-09-13)
LIN, HC
;
LIN, HY
;
CHANG, CY
;
LEI, TF
;
WANG, PJ
The deposition of in situ heavily boron-doped polycrystalline silicon (poly-Si) films was studied using an ultrahigh vacuum/chemical vapor deposition system. Fully activated carrier concentrations up to 3X10(20) cm-3 were obtained for the as-deposited films grown at 550-degrees-C. For boron concentration beyond this level, the crystallinity of poly-Si films degraded with increasing boron concentration, which resulted in an anomalous rise in resistivity. This crystallinity degradation occurred at a higher rate for films grown on a SiO2 surface than those grown on an undoped poly-Si surface. It is attributed to the preferential adsorption of boron atoms on the SiO2 surface. Under a high B2H6 flux condition, a large amount of boron atoms would accumulate on the SiO2 Surface before the formation of Si nuclei, and thus disturbs the subsequent film deposition and grain growth processes.
NOVEL PHENOMENON OF THE AL-1 WT-PERCENT-SI CONTACTS ON THE NF3/AR POST-ETCHING-TREATED N-SI SUBSTRATES
(1993-09-15)
CHENG, HC
;
CHEN, YE
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JUANG, MH
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YEN, PW
;
LIN, L
Post-etching treatment (PET) using an in situ NF3/Ar low-energy plasma was reported to be efficient in removing the residual layer and defects caused by reactive ion etching (RIE) as well as producing a clean surface conventionally believed suitable for electrical contacts. However, the PET process was found to increase the contact resistance between Al-1 wt%Si and n+-Si substrate for the first time. It is attributed to the formation of p-type-like Si epitaxy on the n+-Si substrate and the lower effective surface donor concentration.
EFFECT OF MAGNESIUM ON MECHANICAL-PROPERTIES OF ALUMINA-FIBER-REINFORCED ALUMINUM-MATRIX COMPOSITES FORMED BY PRESSURE INFILTRATION CASTING
(1993-09-15)
LIU, TM
;
CHAO, CG
;
交大名義發表
;
材料科學與工程學系
;
National Chiao Tung University
Al-Al2O3 composites containing 0.48%-6.8% Mg in the matrix alloys have been fabricated by pressure infiltration casting. Optical microscopy, scanning electron microscopy and image analysis were used to examine and to analyze the details of the microstructure and the fracture surface. Tensile tests were utilized to evaluate the mechanical properties. The addition of magnesium was found to improve the infiltration and to decrease the porosity of the composites. The tensile strength of the composites increased with increased magnesium content, while elongation remained almost constant (10%).
ELECTRICAL CHARACTERISTICS OF WO3-BASED CO2-SENSITIVE SOLID-STATE MICROSENSOR
(1993-09-15)
CHAO, S
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交大名義發表
;
電子物理學系
;
National Chiao Tung University
;
Department of Electrophysics
A WO3-impregnated thin polymer across two closely spaced microelectrodes is employed as a solid-state CO2 microsensor at 1 atm and room temperature. Its function is based on the WO3 transformation to the conducting H. WO by intercalation of released protons from CO2 equilibration in the polymer. The response to CO2 concentrations is reversible and linear between approximately 0-16% at approximately 840 kOMEGA per 1% change over prolonged operations of approximately 80-second switching time. A dependence on residual water in the polymer is detected but exerts no influence on the CO response as long as the polymer is not entirely dried out by H2O-free gas.
INTEGRATING AND AUTOMATING ANALYSIS AND OPTIMIZATION
(1993-09-17)
YANG, TC
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TSENG, CH
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交大名義發表
;
機械工程學系
;
National Chiao Tung University
The development of an interface coupling program on personal computers for an analysis software system such as ANSYS, SAP, etc. and an optimization software system, MOST, is presented. By controlling and directing the communications the interface coupler integrates the two programs while retaining their versatility and interactive features. The integrated system is used to solve a numerical example of active noise control for a three-dimensional enclosure, in which an energy density level of control points is minimized by adding the sound source to cancel the unwanted noise. The interface coupling program automates with relatively low cost the iterative process for designing an engineering system, remaining flexible in acoustical modelling and efficient in equation solving. Also, the coupling interface is developed in a general-purpose way so that it can be expanded easily to integrate more analysis software packages of different kinds.
現代俳句
(1993-09-26)
管管
AM3(P2O7)2 (A = ALKALINE-EARTH METALS - M = FE, CO, NI) - DIPHOSPHATES CONTAINING INFINITE CHAINS OF EDGE-SHARING MO6 OCTAHEDRA
(1993-09-29)
LII, KH
;
SHIH, PF
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CHEN, TM
;
應用化學系
;
Department of Applied Chemistry
Diphosphates of the stoichiometry AM3(P2O7)2 (A = alkaline-earth metals; M = Fe, Co, Ni) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Crystal data: CaNi3(P2O7)2, monoclinic, P2(1)/c, a = 7.330(3) angstrom, b = 7.589(3) angstrom, c = 9.400(3) angstrom, beta = 11 1.90(3)-degrees, V = 485.1(3) angstrom3, Z = 2, and R = 0.026; CaCo3(P2O7)2, as above except a = 7.394(l) angstrom, b = 7.6266(9) angstrom, c = 9.444(2) angstrom, beta = 11 1.73(2)-degrees, V = 494.7(l) angstrom3, and R = 0.035; SrFe3(P2O7)2, as above except a = 7.553(l) angstrom, b = 7.7477(8) angstrom, c = 9.5796(8) angstrom, beta = 112.11(1)-degrees, V = 519.4(l) angstrom3, and R = 0.029. The three compounds are isostructural, consisting of zigzag infinite chains of MO6 octahedra sharing either trans or skew edges. The infinite chains arc connected by P2O7 groups to form a three-dimensional architecture with channels parallel to the b axis. Alkaline-earth metals are located in sites within the channels. The following isostructural compounds have also been prepared: AM3(P2O7)2 (A = Sr, Ba; M = Ni, Co) and BaFe3(P2O7)2. A magnetic susceptibility study on SrFe3(P2O7)2 indicates that the material is paramagnetic with an effective magnetic moment of 5.07 mu(B) per Fe between 300 and 26 K. Below this temperature the magnetic susceptibility increases sharply to a maximum at 6 K and then decreases rapidly. Mossbauer spectra also confirm the presence of Fe(II).
WIDE-BAND 32X32 STAR COUPLER MODULE WITH GAIN
(1993-09-30)
GUO, WY
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CHEN, YK
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ZENG, JY
;
CHI, S
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光電工程學系
A wideband 32 x 32 star coupler module using two fibre amplifiers is presented. Not only can the loss of this module be fully compensated for but also it has better loss uniformity. The power margin increment of 18dB is achieved with this module in a 1.7 Gbit/s system experiment.
FORCED VIBRATION OF FLEXIBLE BODY SYSTEMS - A DYNAMIC STIFFNESS METHOD
(1993-10-01)
LIU, TS
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LIN, JC
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交大名義發表
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機械工程學系
;
National Chiao Tung University
Due to the development of high speed machinery, robots, and aerospace structures, the research of flexible body systems undergoing both gross motion and elastic deformation has seen increasing importance. The finite element method and modal analysis are often used in formulating equations of motion for dynamic analysis of the systems which entail time domain, forced vibration analysis. This study develops a new method based on dynamic stiffness to investigate forced vibration of flexible body systems. In contrast to the conventional finite element method, shape functions and stiffness matrices used in this study are derived from equations of motion for continuum beams. Hence, the resulting shape functions are named as dynamic shape functions. By applying the dynamic shape functions, the mass and stiffness matrices of a beam element are derived. The virtual work principle is employed to formulate equations of motion. Not only the coupling of gross motion and elastic deformation, but also the stiffening effect of axial forces is taken into account. Simulation results of a cantilever beam, a rotating beam, and a slider crank mechanism are compared with the literature to verify the proposed method.
THE DELAY ANALYSIS IN A NOISY GENERAL CUT-THROUGH SWITCHING NETWORK
(1993-10-01)
CHANG, CJ
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CHIU, JH
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LIN, SJ
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電信研究中心
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Center for Telecommunications Research
The transfer delay of data packet in a noisy n-node tandem network with general cut-through switching is analyzed in this paper. By assuming each node as an M/G/1 and considering error control done only at the store-and-forward node and done at every node, respectively, the transfer delays of a data packet are determined. Both delays are illustrated and compared in numerical examples. Also, proof of the equality of the transfer delays for the two error control strategies in error free network are conducted to help verifying the validity of the analysis.
THE ANALYSIS OF LINEAR ROTOR-BEARING SYSTEMS - A GENERAL TRANSFER-MATRIX METHOD
(1993-10-01)
LEE, AC
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SHIH, YP
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KANG, Y
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交大名義發表
;
機械工程學系
A general transfer matrix method (GTMM) is developed in the present work for analyzing the steady-state responses of rotor-bearing systems with an unbalancing shaft. Specifically, we derived the transfer matrix of shaft segments by considering the state variables of shaft in a continuous system sense to give the most general formulation. The shaft unbalance, axial force, and axial torque are all taken into consideration so that the completeness of transfer matrix method for steady-state analysis of linear rotor-bearing systems is reached. To demonstrate the effectiveness of this approach, a numerical example is presented to estimate the effect of three-dimensional distribution of shaft unbalance on the steady-state responses by GTMM and finite element method (FEM).
SYNTHESIS AND CHARACTERIZATION OF NOVEL FLUORINATED DIPHENYLDIACETYLENIC LIQUID-CRYSTALS
(1993-10-01)
JUANG, TM
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CHEN, YN
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LUNG, SH
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LU, YH
;
HSU, CS
Five series of asymmetric diphenyldiacetylenes containing a single fluorine, two fluorines or a trifluoromethyl group at one end and an alkyl, alkyloxy or alkenyloxy group on the other end, were prepared and characterized. Most of the 4-alkylphenyl-4'-fluorophenyldiacetylenes, 4-alkyloxyphenyl-4'-fluorophenyl-diacetylenes and 4-alkenyloxyphenyl-4'-fluorophenyldiacetylenes obtained exhibit an enantiotropic nematic phase and no smectic phase. However, most of the 4-alkyl-3', 4'-difluorodiphenyldiacetylenes, 4-alkenyloxy-3',4'-difluorodiphenyl-diacetylenes and 4-alkyl-4'-trifluoromethyldiphenyldiacetylenes show no meso-morphic behaviour. The effects of alkyl, alkyloxy, alkenyloxy, fluoro, 3,4-difluoro and trifluoromethyl end groups on the mesomorphic behaviour of the diphenyldiacetylenes prepared are discussed.
OPTIMAL PERIODIC CONTROL IMPLEMENTED AS A GENERALIZED SAMPLED-DATA HOLD OUTPUT-FEEDBACK CONTROL
(1993-10-01)
YEN, NZ
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WU, YC
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電控工程研究所
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Institute of Electrical and Control Engineering
In this note, a conversion method to convert the analog linear quadratic regulation control to a generalized sampled-data hold output feedback control for a linear periodic system or a linear time-invariant system is presented. It is shown that by using such a conversion, one can implement the optimal periodic control scheme in the presence of incomplete and delayed state measurements.
INVESTIGATION OF SI-SIO2 INTERFACE PROPERTIES FOR BONDED SILICON-ON-INSULATOR
(1993-10-01)
YEH, CF
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KAO, HW
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CHANG, BS
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CHANG, KL
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交大名義發表
A ROBUST OVER-THE-CELL CHANNEL ROUTER
(1993-10-01)
CHANG, LD
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HSIAO, PY
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YAN, JT
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SHEW, PW
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資訊工程學系
In this paper, we present an efficient algorithm for over-the-cell routing in the standard cell layout design technology. Two variations are discussed: one aims to minimize the channel density with fewest tracks over the cells while the other aims to minimize the final channel width. Our algorithm can fit both the two-layer and three-layer routing models. With the two-layer model, there is a single routing layer over the cells for intercell connections. While with the three-layer model, there are two disjoint routing layers over the cells for intercell connections. In our approach, we decompose the problem into two phases: (1) over-the-cell routing and (2) conventional channel routing. The over-the-cell routing phase, which is executed iteratively, consists of two steps, routing over the cells and choosing net segments within the channel. For each iteration in the over-the-cell routing phase, our algorithm removes a net or a subnet which intersects the column with highest column density and route it over the cells according to some prioritized criteria. In comparison with the previous researches, our approach achieved the best effectiveness and has used the least CPU-time. On the average, the execution speed of our router is 163 and 4163 times faster than that of [8] and [9], respectively. Besides, our algorithm can produce results comparable to those produced by the WISER algorithm [10].
EVIDENCE OF ZERO POTENTIAL SPIKE ENERGY IN ALGAAS GAAS HETEROSTRUCTURE EMITTER BIPOLAR-TRANSISTORS
(1993-10-01)
CHEN, HR
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LEE, CP
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CHANG, CY
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TSAI, KL
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TSANG, JS
The potential spike energy at the emitter junction of AlGaAs/GaAs heterostructure emitter bipolar transistors (HEBT) was directly measured for the first time. Experimental data revealed that emitter thickness as thin as 300 angstrom is thick enough to eliminate potential spike without compositional grading. It is found that the band bending in n-GaAs reduces the potential spike and hence very low offset voltage of 70 mV with high current gain of 150 can be obtained.
SLIDING-MODE CONTROLLER-DESIGN FOR SPACECRAFT ATTITUDE TRACKING MANEUVERS
(1993-10-01)
CHEN, YP
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LO, SC
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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
This paper presents a robust sliding-mode control law to deal with the spacecraft attitude tracking problems. Two important natural properties related to the spacecraft model of motion are shown and then by using these properties and the second method of Lyapunov theory, the system stability in the sliding mode can be easily achieved. The success of the sliding-mode controller and the robustness to uncertainties are illustrated by an example of multiaxial attitude tracking maneuvers.
ANALOG STUDY OF BIFURCATION STRUCTURES IN A VANDERPOL OSCILLATOR WITH A NONLINEAR RESTORING FORCE
(1993-10-01)
KAO, YH
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WANG, CS
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電信工程研究所
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光電工程研究所
;
Institute of Communications Engineering
The injection locking and chaotic transitions in a Van der Pol oscillator with a nonlinear-restoring-force term were investigated in this article via an electronic circuit. Three types of locking processes were differentiated from each other in light of local and global bifurcations. The influences of the nonlinear restoring force on the bifurcation structure were also discussed.
RAMAN-SCATTERING OF THIN-FILM C-60/C-70 FULLERENES
(1993-10-01)
LO, KL
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LEE, MC
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交大名義發表
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電子物理學系
;
National Chiao Tung University
High quality thin film fullerenes of C60, C70, and 50% mixture C60/70 were studied by Raman scattering. We observed not only ten complete (2A(g) + 8H(g)) modes in C60, which are assigned in accordance with the point group of a truncated icosahedron, but also drastically more (38) lines in C70, that is owing to the reduced symmetry. By measuring the 50% mixture sample, we were able to distinguish the features of C60 from that of C70. Most of the C60 modes appear at higher frequencies with respect to the corresponding C70 Modes, that is consistent with the cluster-mass difference. We also noticed the lower scattering efficiency Of C60 than that of C70, except the pinch A(g) mode at 1468 cm-1.