Browsing by Issue Date, starting with "1998-11-01"

Now showing 1 - 20 of 81783

The effect of native oxide on thin gate oxide integrity
(1998-11-01)
Chin, A
;
Lin, BC
;
Chen, WJ
;
Lin, YB
;
Thai, C
We have studied the effect of native oxide on thin gate oxide integrity. Much improved leakage current of gate oxide can be obtained by in situ desorbing the native oxide using a HF-vapor treated and H-2 backed process. Furthermore, extremely sharp interface between oxide and Si is obtained, and good oxide reliability is achieved even under a high current density stress of 11 A/cm(2) and a large charge injection of 7.0 x 10(4) C/cm(2). The presence of native oxide will increase the interface roughness, gate oxide leakage current and stress-induced hole trap.
An extraction method to determine interconnect parasitic parameters
(1998-11-01)
Chao, CJ
;
Wong, SC
;
Chen, MJ
;
Liew, BK
;
電子工程學系及電子研究所
Interconnect parasitic parameters in integrated circuits have significant impact on circuit speed. An accurate monitoring of these parameters can help to improve interconnect performance during process development, provide information for circuit design, or give useful reference for circuit failure analysis. Existing extraction methods either are destructive (such as SEM measurement) or can determine only partial parasitic parameters (such as large capacitor measurement), In this paper, we present a new method for extracting interconnect parasitic parameters, which can simultaneously determine the interlayer and intralayer capacitances, line resistance, and effective line width. The method is based on two test patterns of a same structure with different dimensions. The structure consumes less wafer area than existing methods. The method shows good agreement with SEM measurement of dielectric thickness in both nonglobal planarized and chemical-mechanical polished processes, and gives accurate prediction of the process spread of a ring oscillator speed over a wafer.
DMTS: A distributed multimedia teleworking system
(1998-11-01)
Yuang, MC
;
Liu, JG
;
Chen, YG
;
Liu, JC
;
資訊工程學系
Multimedia systems combine a variety of information sources, such as voice, graphics, animation, images, and full-motion video, into a wide range of applications. The paper initially categorizes existing multimedia applications into three classes: noninteractive-oriented, interactive-oriented client-server-based, and interactive-oriented peer-party-based. In particular, the paper examines interactive-oriented applications and provides an in-depth survey of the media synchronization problem for the design of these applications. The paper then presents our prototyping system, called the Distributed Multimedia Teleworking System (DMTS), which allows two or more remote systems in collaboration to access and modify multimedia data through a network in a fully synchronous fashion. The system has been developed over TCP/IP and an FDDI network, using an XVideo D/A card. The media supported by DMTS include text, graphics, voice, and video. DMTS employs a master-slave collaboration model to maintain the coherence of the text and graphics data being simultaneously modified. Moreover, DMTS also adopts effective mechanisms to reduce skew (asynchrony) and jitter delays between video and voice streams. Finally, the paper demonstrates that DMTS achieves a maximum throughput of 13 frames per second, and reveals that the throughput bottleneck resides in the hardware capture and D/A processing of video frames.
Differential conductance of a saddle-point constriction with a time-modulated gate-voltage
(1998-11-01)
Tang, CS
;
Chu, CS
;
電子物理學系
;
Department of Electrophysics
This work investigates how a time-modulated gate-voltage influences the differential conductance G of a saddle-point constriction. The constriction is modeled by a symmetric saddle-point potential and the time-modulated gate-voltage is represented by a potential of the form V(0)Theta(a/2 - x - x(c)) cos(omega t). For h omega less than half of the transverse subband energy level spacing, gate-voltage-assisted (suppressed) feature occurs when the chemical potential mu is less (greater) than but close to the threshold energy of a subband. Our results indicate that as mu increases, G exhibits, alternatively, the assisted and the suppressed feature. For a larger h omega, these two features may overlap. In addition, dip structures are found in the suppressed regime, and mini-steps are found in the assisted regime only when the gate-voltage covers a region sufficiently distant from the center of the constriction. (C) 1998 Elsevier Science B.V. All rights reserved.
Modular recurrent neural networks for Mandarin syllable recognition
(1998-11-01)
Chen, SH
;
Liao, YF
;
電信工程研究所
;
Institute of Communications Engineering
A new modular recurrent neural network (MRNN)-based speech-recognition method that can recognize the entire vocabulary of 1280 highly confusable Mandarin syllables is proposed in this paper, The basic idea is to first split the complicated task, in both feature and temporal domains, into several much simpler subtasks involving subsyllable and tone discrimination, and then to use two weighting RNN's to generate several dynamic weighting functions to integrate the subsolutions into a complete solution. The novelty of the proposed method lies mainly in the use of appropriate a priori linguistic knowledge of simple initial-final structures of Mandarin syllables in the architecture design of the MRNN, The resulting MRNN is therefore effective and efficient in discriminating among highly confusable Mandarin syllables. Thus both the time-alignment and scaling problems of the ANN-based approach for large-vocabulary speech-recognition can be addressed. Experimental results show that the proposed method and its extensions, the reverse-time MRNN (Rev-MRNN) and bidirection MRNN (Bi-MRNN), all outperform an advanced HMM method trained with the MCE/GPD algorithm in both recognition-rate and system complexity.
Direct focusing modifications of elliptical Gaussian beam by non-circular apertures
(1998-11-01)
Chan, SH
;
Shiue, SG
;
Lu, MH
;
光電工程研究所
;
Institute of EO Enginerring
For focusing the elliptical Gaussian beam directly, the effects of a non-circular aperture on the focusing properties are studied. The focusing properties for different shapes of apertures, which include a circle, an ellipse and a rectangle, are calculated and compared. Moreover, for different elliptical Gaussian beams, an empirical aperture selection rule that can be used to circularize the focusing spot is proposed. The energy transmission ratios are also considered in this paper.
Microstructure and nonlinear properties of microwave-sintered ZnO-V2O5 varistors: I, effect of V2O5 doping
(1998-11-01)
Kuo, CT
;
Chen, CS
;
Lin, IN
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The modification of the densification behavior and the grain-growth characteristics of the microwave-sintered ZnO materials, caused by the incorporation of V2O5 additives, have been systematically studied. Generally, the addition of V2O5 markedly enhances the densification rate, such that a density as high as 97.9% of the theoretical density and a grain size as large as 10 mu m can be attained for a sintering temperature as low as 800 degrees C and a soaking time as short as 10 min. Increasing the sintering temperature or soaking time does not significantly change the sintered density of the ZnO-V2O5 materials but it does monotonously increase their grain size. Varying the proportion of V2O5 in the range of 0.2-1.0 mol% does not pronouncedly modify such behavior. The leakage current density (J(L)) of these high-density and uniform-granular-structure samples is still large, which is amended by the incorporation of 0.3 mol% of Mn3O4 in the ZnO materials, in addition to 0.5 mol% of the V2O5 additives. Samples that are obtained using such a method possess good nonohmic characteristics (alpha = 23.5) and a low leakage current density (J(L) = 2.4 x 10(-6) A/cm(2)).
Properties of sputtered Cr-O and reactively sputtered Cr-N-O as passivation layers against copper oxidation
(1998-11-01)
Chuang, JC
;
Chen, MC
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Passivation layers of 200 Angstrom sputtered Cr-O as well as reactive sputtered Cr-N-O were studied with respect to the passivation capability against thermal oxidation of Cu in flowing nitrogen and flowing oxygen ambients. In a flowing N-2 ambient, both Cr-O and Cr-N-O passivation layers were able to prohibit oxidation of Cu at temperatures up to 700 degrees C. In an O-2 ambient, the passivation capability of Cr-N-O layer was found to be 500 degrees C, which is 150 degrees C higher than that of Cr-O layer. The superiority of the passivation capability of the Cr-N-O layer is presumably due to decoration of the surface defects and grain boundaries with nitrogen, which provide fast paths for oxygen and copper diffusion. (C) 1998 American Vacuum Society. [S0734-211X(98)11706-7].
Microstructure and nonlinear properties of microwave-sintered ZnO-V2O5 varistors: II, effect of Mn3O4 doping
(1998-11-01)
Kuo, CT
;
Chen, CS
;
Lin, IN
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The microstructure and nonlinear current-voltage characteristics of Mn3O4-doped ZnO-V2O5 ceramics, microwave-sintered at 800 degrees-1200 degrees C for 10 min, have been investigated. A high density (96% of the theoretical density) has been achieved. The incorporation of Mn3O4 additives does not significantly alter the densification behavior of the ZnO-V2O5 materials, but rather pronouncedly increases the non-linear coefficient (alpha = 23.5) and markedly suppresses their leakage current density (J(L) = 2.4 x 10(-6) A/cm(2)). On the other hand, the intrinsic properties of the materials, including the Schottky barrier height (Phi(b)) and the donor density (N-d), are only moderately modified; that is, Phi(b) = 1.16 eV and N-d = 5.4 x 10(17)/cm(3). X-ray diffractometry analyses and energy-dispersive X-ray microanalyses (via scanning electron microscopy) indicate that the V2O5 species facilitate the densification and the development of microstructure via the formation of a liquid phase (Zn-3(VO4)(2)) along the grain boundaries, whereas the Mn3O4 species markedly enhance the nonohmic behavior of the ZnO-V2O5 materials by forming the surface states along the grain boundaries.
Effect of glass addition on microwave properties of BaO center dot La2O3 center dot 4.7TiO(2)
(1998-11-01)
Lee, CC
;
Lin, P
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effects of the addition of glass to the microwave properties of BaO . La2O3. 4.7TiO(2) ceramics were investigated. Three commercial glasses. PbO-B2O3-SiO2 (GA9), ZnO-B2O3-SiO2 (GP032) and PbO-Ba2O3 (LS3081), were investigated in this study. The ceramics without glass addition and sintered at 1300 degrees C gave the relative dielectric constant epsilon(r) = 92, quality factor Q = 1653 and temperature coefficient of resonant frequency tau(f) = 40.3 ppm/degrees C at 3.0 GHz. With 20 wt% GA9 addition. highly dense samples (void fraction were less than or equal to 2.5 vol%) were obtained at T, greater than or equal to 900 degrees C and their microwave properties were: epsilon(r) greater than or equal to 64, Q greater than or equal to 1037 and tau(f) less than or equal to 15.3 ppm/degrees C at 3.0 GHz. The high sintering temperature increased epsilon(r) and Q values but decreased the value of tau(f). The densification of specimens was found to play an important role in improving the dielectric constant. Heterogeneous interfaces and the dissolution of trace amounts of ceramics in glass increased the dielectric loss significantly; also, the former increased tau(f) whereas the latter decreased it.
MPT-based branch-and-bound strategy for scheduling problem in high-level synthesis
(1998-11-01)
Hsiao, PY
;
Wu, GM
;
Su, JY
;
電機資訊學士班
;
Undergraduate Honors Program of Electrical Engineering and Computer Science
A branch-and-bound algorithm based on a maximum possibility table (MPT) is proposed to solve scheduling problems in high-level synthesis. Six efficient priority rules are developed as bounding functions in the algorithm. Extensions for real-world constraints are also considered, including chained operations, multicycle operations, mutually exclusive operations and pipelined data paths. Experimental results indicate that the MPT-based algorithm returns competitive scheduling results at significant savings in execution time as compared with other methods.
Nonlinear optical chromophores with configuration-locked polyenes possessing enhanced thermal stability and chemical stability
(1998-11-01)
Shu, CF
;
Shu, YC
;
Gong, ZH
;
Peng, SM
;
Lee, GH
A synthetic strategy has been developed for preparation of NLO chromophores with all the pi-conjugated methine groups incorporated into plane-rigidified, fused, six-membered rings. The comparison of the rigidified chromophores to the analogous nonrigid chromophores shows that the configuration-locking methods provide a dramatic enhancement of molecular thermal stability. The data from W-vis spectroscopy and X-ray crystallography reveal that the rigidity of the annulated rings does not diminish the planarity and the electron delocalization efficiency of the polyenic chain.
Data hiding in images via multiple-based number conversion and lossy compression
(1998-11-01)
Wu, DC
;
Tsai, WH
;
資訊工程學系
;
Department of Computer Science
A novel and easy method to embed any form of secret messages into a cover image with controlled distortion is proposed. Any lossy image compressor may be applied first to a cover image to produce a lossily-processed result as the basis for embedding data in the cover image. The stego-image is produced by embedding data in each pixel of a cover image by changing its gray value without excessing the range of the gray value difference of the corresponding pixels of the cover image and its lossily-processed one. The quantity of distortion that is caused by embedding data is never in excess of that is caused by the lossy compressor. A multiple-based number system is proposed to convert the information in the secret bit stream into values to be embedded in the choosing pixels of the cover image. Pseudo-random mechanisms may be used to achieve cryptography. It is found from experiments that the values of the peaks of the signal-to-noise ratio of the stego-images are larger than those yielded by the chosen compressor, which means that the distortion in the embedding result is more imperceptible than that in the compressed one.
DMTS: A distributed multimedia teleworking system
(1998-11-01)
Yuang, MC
;
Liu, JG
;
Chen, YG
;
Liu, JC
;
資訊工程學系
Multimedia systems combine a variety of information sources, such as voice, graphics, animation, images, and full-motion video, into a wide range of applications. The paper initially categorizes existing multimedia applications into three classes: noninteractive-oriented, interactive-oriented client-server-based, and interactive-oriented peer-party-based. In particular, the paper examines interactive-oriented applications and provides an in-depth survey of the media synchronization problem for the design of these applications. The paper then presents our prototyping system, called the Distributed Multimedia Teleworking System (DMTS), which allows two or more remote systems in collaboration to access and modify multimedia data through a network in a fully synchronous fashion. The system has been developed over TCP/IP and an FDDI network, using an XVideo D/A card. The media supported by DMTS include text, graphics, voice, and video. DMTS employs a master-slave collaboration model to maintain the coherence of the text and graphics data being simultaneously modified. Moreover, DMTS also adopts effective mechanisms to reduce skew (asynchrony) and jitter delays between video and voice streams. Finally, the paper demonstrates that DMTS achieves a maximum throughput of 13 frames per second, and reveals that the throughput bottleneck resides in the hardware capture and D/A processing of video frames.
An extraction method to determine interconnect parasitic parameters
(1998-11-01)
Chao, CJ
;
Wong, SC
;
Chen, MJ
;
Liew, BK
;
電子工程學系及電子研究所
Interconnect parasitic parameters in integrated circuits have significant impact on circuit speed. An accurate monitoring of these parameters can help to improve interconnect performance during process development, provide information for circuit design, or give useful reference for circuit failure analysis. Existing extraction methods either are destructive (such as SEM measurement) or can determine only partial parasitic parameters (such as large capacitor measurement), In this paper, we present a new method for extracting interconnect parasitic parameters, which can simultaneously determine the interlayer and intralayer capacitances, line resistance, and effective line width. The method is based on two test patterns of a same structure with different dimensions. The structure consumes less wafer area than existing methods. The method shows good agreement with SEM measurement of dielectric thickness in both nonglobal planarized and chemical-mechanical polished processes, and gives accurate prediction of the process spread of a ring oscillator speed over a wafer.
Propagation characteristics of the slotline first higher order mode
(1998-11-01)
Sheen, JW
;
Lin, YD
;
傳播研究所
;
Institute of Communication Studies
The propagation characteristics of the slotline first higher order mode are presented in detail in this paper. It is found that the attenuation constants and the radiation band of this first higher order mode are larger than those of the microstripline first higher order mode. Dependence of the propagation characteristics on structural parameters and the effect of finite-conductor planes are analyzed. The propagation characteristics of the surface-wave-like modes are also discussed. In order to avoid inadvertent excitation of these surface-wave-like modes in antenna applications, the current and field distributions of the slotline first higher order mode and the surface-wave-like modes are compared and discussed. Excitation of the slotline first higher order mode was conducted by feeding the slotline with a coplanar waveguide and microstrip line. Experimental results show good agreement with our numerical results, and also confirm the existence of the slotline first higher order mode.
Industrial development and structural adaptation in Taiwan: Some issues of learned entrepreneurship
(1998-11-01)
Liu, SJ
;
科技管理研究所
;
Institute of Management of Technology
The industrialization of Taiwan has been a remarkable phenomenon. This paper discusses recent changes in Taiwan's manufacturing industries and the response of both government and private enterprises to the challenges presented by a dynamic environment and by global competition. Several cases are discussed in light of the activities and adjustments on the part of government and of the public sector, of small and medium business, and of high-tech industries. Government participation over the last four decades has been and will remain pivotal in economic growth and in achieving adjusted positioning. Taiwan's personal computer and IC industries have evolved from an infant stage through an accelerated growth period and are now extending to other technologically associated industries. The small enterprise sector is in a transitional stage of upgrading competitive niches. The unsuccessful stories of biopharmaceuticals and automobiles are discussed in terms of what they reveal about government intervention and the performance of public research institutes. Active patenting activities by Taiwan enterprises and public research institutes illustrate the accumulated technological capability found on this island. The accelerated sociopolitical movements toward democracy, the bureaucratic management of public issues, and the political and economic interactions between Taiwan and China, exert significant effects on the industrial structure and on government's role in directing the industrial evolution. This article presents an integrated reasoning of Taiwan's economic success, It reveals that the neoclassical doctrine of market efficiency is fundamentally valid, and that the effective commercialization of national technological capability has created Taiwan's industrial evolution. Market governance proved to be an efficient short-term policy instrument when the latecomer strategy of cost leadership was applied. A conceptual model of industrial competition and technology commercialization is also proposed to facilitate the methodological analysis. This study concludes that learning capability and human capital will determine the endurance of Taiwan's industrial success, and that entrepreneurship must be learned by the state, as well as by the private firms.
Data hiding in images via multiple-based number conversion and lossy compression
(1998-11-01)
Wu, DC
;
Tsai, WH
;
資訊工程學系
;
Department of Computer Science
A novel and easy method to embed any form of secret messages into a cover image with controlled distortion is proposed. Any lossy image compressor may be applied first to a cover image to produce a lossily-processed result as the basis for embedding data in the cover image. The stego-image is produced by embedding data in each pixel of a cover image by changing its gray value without excessing the range of the gray value difference of the corresponding pixels of the cover image and its lossily-processed one. The quantity of distortion that is caused by embedding data is never in excess of that is caused by the lossy compressor. A multiple-based number system is proposed to convert the information in the secret bit stream into values to be embedded in the choosing pixels of the cover image. Pseudo-random mechanisms may be used to achieve cryptography. It is found from experiments that the values of the peaks of the signal-to-noise ratio of the stego-images are larger than those yielded by the chosen compressor, which means that the distortion in the embedding result is more imperceptible than that in the compressed one.
A new two-terminal feeding active leaky-wave antenna
(1998-11-01)
Wang, CJ
;
Jou, CF
;
Wu, JJ
;
電信工程研究所
;
Institute of Communications Engineering
A new two-terminal feeding active-integrated leaky-wave antenna design is demonstrated. The S-band microstrip two-terminal feeding leaky-wave antenna is integrated with an active high-electron mobility transistor (HEMT) oscillator to produce a two-beam radiation pattern, The antenna is fed asymmetriclly at both sides to excite the first higher order mode, This configuration, as compared to a single-terminal feeding leaky-wave antenna, has the advantage of the multidirection and the reduction of the reflected wave caused by the open end of the radiating element. Measured results show that the radiation directions of two beams are approximately at 34 degrees and 140 degrees, the effectively isotropic radiated power (EIRP) is close to 17.5 dBm, and the return Loss is almost less than -10 dB between 9 and 11.5 GHz.
Multidimensional interval filter: A new indexing method for subpicture query of image retrieval
(1998-11-01)
Shan, MK
;
Lee, SY
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
In this paper a new indexing method, called multidimensional interval filter, is proposed to speed up processing of subpicture query. The basic idea is the transformation of spatial information of each image into a multidimensional rectangle. Processing of subpicture query becomes that of rectangle containment query which can be further speeded up by some well-developed spatial access methods such as R-Trees. (C) 1998 Elsevier Science B.V. All rights reserved.