Browsing by Issue Date, starting with "1993-05-24"

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OBSERVATION OF QUANTUM CONFINEMENT EFFECTS IN STRAINED SI0.84GE0.16/SI QUANTUM-WELLS AT ROOM-TEMPERATURE
(1993-05-24)
CHEN, YF
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DAI, YT
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CHOU, HP
;
CHANG, DC
;
CHANG, CY
We report the first study of quantum confinement shifts of energy gap in strained Si0.84Ge0.16/Si quantum wells at room temperature by photothermal deflection spectroscopy (PDS) technique. The experimental results obtained from the amplitude and phase of the PDS signal are in good agreement with quantum well subband calculation.
MANAGING SECURE COMMUNICATIONS WITH MULTILEVEL SECURITY AND RESTRICTED CHARACTER SET TRANSLATION
(1993-06-01)
YANG, C
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TSAI, CC
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管理科學系
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資訊管理與財務金融系註：原資管所+財金所
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Department of Management Science
Naval message traffic is transmitted with restricted character set, the files of which are optionally compressed. Often in this type of transmission, both character set translation and data compression can be used as add-on data encryption. In supporting the multilevel security management of access control in communication, this paper presents a possible implementation of master keys. The underlying basis of this key management scheme allows a set of keys to be maintained in either a floating or connected fashion, thus making the system tolerant to expansion. In doing this, it is discovered that a direct implementation for master keys is not possible as modulo arithmetic is required whereby only the arithmetic operations of addition and multiplication follow the commutative property-not division, where the results of modulo division are irreversible. As a solution to this problem, a recursive procedure of modulo exponentiation is employed via software which utilizes indexes. Along with this research, an algorithm has been implemented with restricted character set translation scheme and incorporated into a data compression program for military applications. The restricted character set translation algorithms investigated for the U.S. Navy are discussed in this paper. The application of character set translation will defer hardware changes, and the software implementation alleviates the need for expensive hardware.
EFFECTS OF A RESISTIVELY COATED DIELECTRIC STRIP ON THE TM-POLARIZED RESONANT BACKSCATTER BEHAVIOR OF A SLOTTED CONDUCTING RECTANGULAR SHELL
(1993-06-01)
WU, LK
;
LU, CH
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交大名義發表
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傳播研究所
;
National Chiao Tung University
The performance of a resistively coated dielectric strip used to suppress the first TM-type resonant backscatter associated with a two-dimensional slotted conducting rectangular shell is analyzed in this paper using the moment method technique. Results obtained indicate that almost perfect resonance damping performances are attained when a finite-dimensioned resistively coated dielectric strip with dielectric constant epsilon(r) = 4-j0.4 and film resistance R(s) = 188.5 OMEGA is placed: (1) at the sw (which directly faces the normally incident TM-polarized plane wave), (2) on the interior perimeter of the shell adjacent to the slot, or (3) at the center of the back wall of the shell. Poorer damping performances are observed, however, when the resistively coated dielectric strip is placed at other positions and/or with the same or higher film Finally, ft is also shown that in general the knowledge of the waveguide theory can be used advantageously in the placement of the resistively coated dielectric strip for achieving best resonance damping performance.
ANALYTICAL DESIGN FORMULATION FOR MINORITY-CARRIER WELL-TYPE GUARD RINGS IN CMOS CIRCUITS
(1993-06-01)
CHEN, MJ
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HUANG, CY
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TSENG, PN
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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
Minority carriers injected from an active emitter into the substrate and partially collected by the bottom well junction in an epitaxial CMOS structure are studied. Two-dimensional numerical simulation has revealed that the minority-carrier collection current along the bottom well junction is contributed primarily by two mechanisms: the first due to minority carriers injected into a layer between the upper collecting plate and the bottom reflecting plate; and the second due to those penetrating the high/low junction and then spreading out in the large, highly-doped bulk as in the nonepitaxial case. Based on this observation, a new analytic model for the minority-carrier escape current has been developed as a measure of well-type guard ring efficiency. This model, including a closed-form expression as function of epitaxial layer thickness, well junction depth and guard ring width, has been confirmed by experimental data as well as by two-dimensional numerical simulation. As predicted by the model, the measured escape current has been found to be dominated by the second mechanism for the case of well junction depth close to epitaxial layer thickness while the first mechanism has been identified to dominate the escape current measured from the structure having sufficient epitaxial layer thicknesses.
FAULT ANALYSIS ON (K+1)-VALUED PLA STRUCTURE LOGIC-CIRCUITS
(1993-06-01)
WANG, HM
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LEE, CL
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CHEN, JE
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交大名義發表
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電子物理學系
This paper presents a general form and a set of basic gates to implement (K+1)-valued PLA structure logic circuits. A complete fault analysis on the proposed circuit has been done and it is shown that all fanout stem faults can be collapsed to branch faults. A procedure for fault collapsing is derived. For any function implemented in the (K+1)-valued circuit, the number of remaining faults is smaller than that of the 2-valued circuit after the collapsing, where the value of K is dependent on the number of outputs and the assignment of the OR plane of the 2-valued logic circuit.
DRESSING EFFECT ON THE ELECTRON-ATOM SCATTERING IN INTENSE LASER FIELD
(1993-06-01)
HAN, CS
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交大名義發表
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電子物理學系
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National Chiao Tung University
;
Department of Electrophysics
The dressing effect on the electron-atom scattering in an intense laser field is investigated by solving the time-dependent Schrodinger equation in momentum space. It is found that the result of previous works in the literature is only a limiting case of ours. Our method gives a general formulation for the discussion of the dressing effect during the scattering process.
EXISTENCE OF MANY POSITIVE NONRADIAL SOLUTIONS FOR NONLINEAR ELLIPTIC-EQUATIONS ON AN ANNULUS
(1993-06-01)
LIN, SS
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交大名義發表
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應用數學系
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National Chiao Tung University
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Department of Applied Mathematics
THE CHARACTERIZATION OF AL2O3 PREPARED BY ANODIC-OXIDATION
(1993-06-01)
YEH, CF
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CHENG, JY
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LU, JH
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交大名義發表
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電控工程研究所
Aluminum is a good candidate of low resistivity metal as a gate electrode metal and a gate bus-line metal in amorphous silicon thin-film transistor of liquid crystal display. But it easily brings about hillocks and whiskers during the heat process, and causes defects. Al2O3 formed on aluminum layer is expected to work as a protective layer against hillock formation. The formation of Al2O3 is developed by anodic oxidation method. The electrical characteristics of Al2O3 layers formed at constant DC anodic bias or constant DC current density were investigated. The optimal growth condition of Al2O3 has been developed. In addition, the double-layer of Al2O3/SiN is also shown to be sufficiently protective against hillock formation.
TRANSIENT AND STEADY-STATE CARRIER TRANSPORT UNDER HIGH-FIELD STRESSES IN SONOS EEPROM DEVICE
(1993-06-01)
LIN, JK
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CHANG, CY
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HUANG, HS
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HO, TS
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CHEN, KL
The carrier transport model of tunneling oxide in a polysilicon-oxide-nitride-oxide-silicon (SONOS) device has been developed. The model is deduced from WKB approximation, and uses Fermi-Dirac statistics. Using the J-E and accompanied by Arnett's trapping model, the switching behavior of the SONOS device can be predicted in a very wide range of switching times from 1 mus to 0.1 s. The steady-state charge distribution and electric field in Si3N4 are also calculated. From Arnett's fundamental equations of Si3N4, we deduce the steady-state equations which describe the electric field and trapping charges. The trapping parameters and detrapping factor v are discussed and the results are obtained via computer for different temperatures and stress voltages, which are based on the current measurement of SONOS devices. We find that the detrapping effect is somewhat less dominant compared to the trapping effect in our simulations.
POLARIZATION-SELECTIVE ELEMENTS WITH A SUBSTRATE-MODE GRATING PAIR STRUCTURE
(1993-06-01)
HUANG, YT
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CHEN, YH
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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 novel device with a substrate-mode grating pair structure to perform the function of polarization selection is presented. Normally incident and output coupling of this compact and lightweight component provides better flexibility and easier alignment for system applications. A highly polarization-selective substrate-mode grating pair has been designed and fabricated. Polarization-selective switching experiments with this device are demonstrated.
MODEL-REDUCTION FOR UNSTABLE LINEAR-SYSTEMS
(1993-06-01)
CHIU, TY
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交大名義發表
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電控工程研究所
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National Chiao Tung University
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Institute of Electrical and Control Engineering
Consider the unstable linear multivariable systems. The model reduction algorithm based on balancing and truncation technique for unstable systems will be given. If the unstable system can be ''balanced,'' then the balancing and truncation algorithm gives a reduced order model which (i) has the same number (McMillan degree) of unstable poles as the original model, and (ii) has an error bound which is similar to the case where the system is stable.
CSMA/CD PROTOCOL FOR TIME-CONSTRAINED COMMUNICATION ON BUS NETWORKS
(1993-06-01)
JAN, RH
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YEH, YJ
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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
A multiple access protocol for transmitting time-constrained packets on bus networks is presented. Based on carrier sense multiple access/collision detection (CSMA/CD) protocol, a new protocol is developed and its performance evaluated by computer simulation. An approximate analysis model for this protocol is also presented. Numerical results indicate that the new protocol achieves a better performance, and the approximate analysis model is also effective.
SUBARRAY-SYNTHESIZED LOW-SIDE-LOBE SUM AND DIFFERENCE PATTERNS WITH PARTIAL COMMON WEIGHTS
(1993-06-01)
LEE, TS
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TSENG, TK
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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
New methods of synthesizing low-side-lobe sum and difference patterns for linear arrays are described. By subarray beam forming, the sum and difference patterns exhibit a common factor, leading to a simple monopulse estimator. A procedure is proposed for the synthesis of the subarray-based sum and difference patterns which approximate a set of reference patterns in least-squares sense. Supervised nulling is incorporated as a means of suppression of strong interference. To further reduce system complexity, we impose the constraint that parts of the beam-forming weights are shared by the sum and difference channels. The relationship between the maximum number of common weights allowable and the number of subarrays used is discussed. Numerical results are presented to demonstrate the efficacy of the proposed methods.
VIRTUAL HOPF PRECURSOR OF PERIOD-DOUBLING ROUTE IN DIRECTLY MODULATED SEMICONDUCTOR-LASERS
(1993-06-01)
KAO, YH
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LIN, HT
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電信工程研究所
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電信研究中心
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Institute of Communications Engineering
In this paper the noise effects on the period-doubling route in deeply modulated laser diodes were investigated. The dynamics were studied by employing the single-mode rate equations with consideration of Langevin noise. It was identified that the period-doubling event in laser diodes had a virtual Hopf precursor and was enhanced by the existed Langevin noise.
EVALUATION OF SAFETY OF HYDRAULIC STRUCTURES AFFECTED BY MIGRATING PITS
(1993-06-01)
TUNG, YK
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YEH, KC
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土木工程學系
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Department of Civil Engineering
Because it can be carried by flowing water, a sand/gravel pit on the river bed could migrate downstream. Consequently, the presence of pits on river beds could pose a safety threat to in-stream hydraulic structures such as bridge piers. A pit migration model can be used to predict progressive changes of pit geometry as it migrates downstream. However, due to the existence of many uncertainties, the maximum pit depth cannot be predicted with certainty. This paper adopted a simple pit migration model and evaluated the uncertainty associated with the calculated maximum pit depth. Such information is essential for evaluating the probability that a migrating pit could pose a safety threat to a downstream hydraulic structure. Three reliability analysis techniques were applied and their performances were compared.
A SIMPLE EXPERIMENT OF SIMULATING OPTICAL FLIP-FLOP OPERATOR WITH 2 OSCILLOSCOPES AND PHOTODIODES
(1993-06-01)
WANG, CS
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CHEN, NP
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SHY, JT
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GOU, YS
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光電工程學系
A coupled hybrid optical bistable device composed of two oscilloscopes and two photodiode detectors has been constructed. This device is used to experimentally simulate the basic feature of the flip-flop operator proposed by Otsuka [Opt. Lett. 14 (1989) 72]. Most importantly, it allows us to model the system easily, and hence the condition of an occurrence of the flip-flop operation is accordingly predicted by the linear stability analysis. Furthermore, the influences of symmetry property of the optical system upon the flip-flop operation have been discussed as well.
TUNGSTEN NITRIDE THIN-FILMS PREPARED BY MOCVD
(1993-06-01)
CHIU, HT
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CHUANG, SH
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交大名義發表
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應用化學系
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National Chiao Tung University
Polycrystalline tungsten nitride thin films were grown by low pressure metallo-organic chemical vapor deposition (MOCVD) using (tBuN)2W(NHtBu)2 as the single-source precursor. Deposition of uniform thin films on glass and silicon substrates was carried out at temperatures 723-923 K in a cold-wall reactor, while the precursor was vaporized at 333-363 K. The growth rates were 2-10 nm/min depending on the condition employed. Bulk elemental composition of the thin films, studied by wavelength dispersive spectroscopy (WDS), is best described as WN(x) (x = 0.7-1.8). The N/W ratio decreased with increasing temperature of deposition. X-ray diffraction (XRD) studies showed that the films have cubic structures with the lattice parameter a = 0.414-0.418 nm. The lattice parameter decreased with decreasing N/W ratio. Stoichiometric WN thin films showed an average lattice parameter a of 0.4154 nm. X-ray photoelectron spectroscopy (XPS) showed that binding energies of the W4f7/2, W4f5/2, and N1s electrons were 33.0, 35.0, and 397.3 eV, respectively. Elemental distribution within the films, studied by secondary ion mass spectroscopy (SIMS) and Auger spectroscopy depth profilings, was uniform. The SIMS depth profiling also indicated that C and 0 concentrations were low in the film. Volatile products trapped at 77 K were analyzed by gas chromatography-mass spectroscopy (GC-MS) and nuclear magnetic resonance (NMR). Isobutylene, acetonitrile, hydrogen cyanide, and ammonia were detected in the condensable mixtures. Possible reaction pathways were proposed to speculate the origin of these molecules.
TRANSMISSION COEFFICIENTS IN THE ELECTRON-ATOM SCATTERING IN INTENSE LASER FIELD
(1993-06-01)
HAN, CS
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交大名義發表
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電子物理學系
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National Chiao Tung University
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Department of Electrophysics
A non-perturbative method is used to investigate the one-dimensional problem of the electron-atom scattering in the presence of intense field by solving the time-dependent Schrodinger equation in momentum space. The exact results of the transmission and reflection coefficients for the system are derived. Some errors in the previous heuristic results are found.
CARBON INCORPORATION DURING GROWTH OF GAAS BY TEGA-ASH3 BASE LOW-PRESSURE METALORGANIC CHEMICAL-VAPOR-DEPOSITION
(1993-06-01)
CHEN, HD
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CHANG, CY
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LIN, KC
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CHAN, SH
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FENG, MS
Heavily carbon-doped GaAs (1 X 10(18) approximately 1 X 10(20) cm-3) grown by low-pressure metalorganic chemical vapor deposition using triethylgallium and arsine as sources and liquid carbon-tetrachloride (CCl4) as dopant has been investigated. The carrier concentration was verified at various growth temperatures, V/III ratios, and CC]4 flow rates. Dopant concentration first increased from 550-degrees-C and reached a maximum at 570-degrees-C growth temperature (T(g)) and then decreased monotonously. Carbon incorporation was strongly enhanced when the V/III ratio was less than 30 at T(g) = 590-degrees-C or less than 40 at T(g) = 630-degrees-C. Hole concentration increased and then decreased as CCl4 flow rate increased. Growth rate of layers decreased as growth temperature and flow rate Of CCl4 increased. The doping efficiency of epitaxial layers grown on the (100) substrate was higher than that on the 2-degrees off toward [110] misoriented substrate. Carbon-doped GaAs films had higher Hall mobility than zinc-doped GaAs films at high doping levels due to less self-compensation. The highest dopant concentration in this system was 2.3 X 10(20) cm-3 at T(g) = 580-degrees-C and V/III = 10.
METALLIZATION OF ALUMINUM NITRIDE SUBSTRATES BY ELECTROLESS COPPER PLATING
(1993-06-01)
CHIOU, BS
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CHANG, JH
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DUH, JG
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電控工程研究所
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Institute of Electrical and Control Engineering
The metallization of AIN substrates by electroless Cu plating was investigated for as-received unpolished and mechanically polished AIN substrates. Four-percent NaOH aqueous solution was employed as the chemical etchant before plating to create sites for mechanical interlocking. For the unpolished substrates, the adhesion increased from 1.3 kg/MM2 for the sample with an average surface roughness of 0.2 mum to 2.3 kg/MM2 for those with an average surface roughness of 0.82 mum. Mechanical interlocking is suggested as the major cause for adhesion in the Cu-unpolished AIN system. The adhesion strength of Cu with respect to the mechanically polished AIN substrate increases to a value larger than 7.6 kg/mm2. This makes electroless Cu plating a good candidate for AIN metallization. Nevertheless, the mechanism that causes the increased adhesion strength for the mechanically polished case needs further investigation.