Browsing by Issue Date, starting with "2004-01-23"

Now showing 1 - 20 of 70756

Intervention of phenonium ion in Ritter reactions
(2004-01-23)
Ho, TL
;
Chein, RJ
;
應用化學系
;
Department of Applied Chemistry
The transformation of phenylethyl chloride to 3,4-dihydroisoquinolines is shown to proceed via phenonium ion. The evidence comes from a study of dideuterated analogue 4, and the monomethylated and dimethylated compounds 2 and 3.
One-polymer active pixel
(2004-01-26)
Tzeng, KL
;
Meng, HF
;
Tzeng, MF
;
Chen, YS
;
Liu, CH
A metal-oxide field-effect transistor (MOSFET) based on an electroluminescent conjugated polymer is fabricated on a glass substrate. It is found that the mobility horizontal to the substrate is two to three orders of magnitude larger than the mobility vertical to the substrate. The high horizontal mobility is attributed to the in-plane chain alignment in amorphous spin-coated films. We demonstrate an active pixel in which the light-emitting diode and the driving MOSFET share the same active polymer. (C) 2004 American Institute of Physics.
A side-chain dendronized nonlinear optical polyimide with large and thermally stable electrooptic activity
(2004-01-27)
Luo, JD
;
Haller, M
;
Li, HX
;
Tang, HZ
;
Jen, AKY
音声信号を送信およびパックするためのデジタル符号化方法およびアーキテクチャ
(2004-01-29)
劉　▲啓▼民
;
李　文傑
【課題】高い品質とより低い計算の複雑さを有する、音声信号の送信およびパックのためのデジタル符号化方法を提供すること。【達成手段】デジタル符号化方法は、入力音声信号を、音声信号のスペクトル構成を表す周波数サンプルのシーケンスに変換し、かつ、これを、マスク閾値を参照することによって量子化パラメータを評価するためのパラメータ予測器を用いるビット割当装置に従い、量子化する。量子化された値は、いくつかのビットからなるデータへと符号化される。繰り返しのレート制御ループが、符号化されるビット数が符号化されるデータに利用可能な指定のビット数を超えると、量子化パラメータおよび量子化ステップサイズを調節する。また、入力音声信号の高周波成分を、繰り返しレート制御ループによって決定されたカットオフ周波数に従って、周波数サンプルのシーケンスを量子化する前にカットオフすることができる。【選択図】　　　図１
Schottky structure in GaAs semiconductor device
(2004-01-29)
Cheng-Shih, Lee
;
Yi, Chang
The present invention provides a Schottky Structure in gallium arsenide (GaAs) semiconductor device, which comprises a gallium arsenide (GaAs) semiconductor substrate, a titanium (Ti) layer on a surface of said gallium arsenide (GaAs) semiconductor substrate to form Schottky contact, a diffusion barrier layer on a surface of said titanium (Ti) layer to block metal diffusion, and a first copper layer on a surface of said diffusion barrier layer.
Evaluation of advanced chemical mechanical planarization techniques for copper damascene interconnect
(2004-01-30)
Chen, KW
;
Wang, YL
;
Liu, CP
;
Yang, K
;
Chang, L
According to rapid development of CMP technology, the difference of polishing methods would be applied for copper damascene interconnect. These methods include conventional rotary, linear, oscillation platform. The advantages of these platform would highlighted in uniformity control, stability of removal rate, planarization efficiency, throughput promotion, lower cost of ownership, even dishing and erosion effect integrated with slurry. This paper presented our experience to compare the uniformity, removal rate and planarization efficiency of Cu-CMP between various polishing platforms. In convection, the rotary or oscillation platform would be usually applied in oxide and tungsten CMP, due to the robust air-back carrier and rigid platen to polish the wafer, which performs the good reliability on wafer-to-wafer thickness and endpoint detection. However, the linear polisher is made of the air-bearing moving belt and self-rotated carrier and would provide the wider uniformity and planarization control window than others. In addition,, the simulation model would explain the difference from mechanic design and wafer moving paths between various polishing techniques. Hence, the trade-off advantage and application between various platforms would be compensated and integrated with slurry, conditioners and coming thickness profile from copper plating. It can achieve the optimization of Cu-CMP process. (C) 2003 Elsevier B.V. All rights reserved.
Study on precipitations of fluorine-doped silicon oxide
(2004-01-30)
Wu, J
;
Wang, YL
;
Liu, CP
;
Chang, SC
;
Kuo, CT
Precipitation on fluorine-doped silicon oxide film (SiOF) was observed while exposure to air for a prolonged period of time (>4 h). Most of the precipitates are less than 1 mum and clustered at wafer center. Under SEM view, the precipitation shows hexagonal shape, and mainly composed of Si and O. SIMS analysis showed that SiOF films without F precipitates showed leveling F% profile, whereas SIMS result for SiOF films with precipitations shows increasing gradient with depth. In this study, factors affecting the precipitation of SiOF film were investigated. Humidity in environment was found to be one of the essential elements for the onset of precipitation. Process optimization and control methodologies were also investigated for precipitation prevention to provide a more robust and stable SiOF film, hence ensuring the reliability of device performance. (C) 2003 Elsevier B.V. All rights reserved.
Copper surface protection with a completely enclosed copper structure for a damascene process
(2004-01-30)
Wang, TC
;
Hsieh, TE
;
Wang, YL
;
Wu, YL
;
Lo, KY
As integrated circuit manufacture moving to copper interconnection for the most advanced products, protection of copper (Cu) surfaces becomes a major challenge for the back-end-of-line manufacturing process. The damages on Cu, such as Cu corrosion and oxidation, are often observed on wafers when exposing bare Cu surface in the presence of moisture and/or acidic gases. Furthermore, the Cu oxide results in poor adhesion both at Cu/barrier layer and Cu/stop layer interfaces. In this work, a novel Cu dual damascene structure which completely encloses the Cu surface with a tantalum nitride layer is presented. This capping layer avoids the Cu corrosion and oxidation due to its ability to keep moisture and acid off and away from the Cu surface. (C) 2003 Elsevier Science B.V. All rights reserved.
Effects of the Sb2Te3 crystallization-induced layer on crystallization behaviors and properties of phase change optical disk
(2004-01-30)
Wang, WH
;
Chung, LC
;
Kuo, CT
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The conventional phase-change optical disk is generally fabricated by the sputtering process, which has a drawback of requiring an initialization process to change the as-deposited recording layer in the disk from amorphous to crystalline phases before the disk can be used for reading or writing. In order to develop an initialization-free process, the Sb2Te3, alloy was used as an additional layer below or above the recording Ge2Sb2Te5 layer to study its effect on crystallization behaviors of the recording layer. The layer structures were deposited on substrates of Si wafer, Cu-mesh to examine crystal structure (XRD), amorphous-to-crystal transformation (DSC) and microstructure (TEM). The complete disk specimens were prepared on PC board to measure their dynamic properties, such as reflectivity, jitter and modulation (dynamic tester); and to examine the effects of laser pulse duration time, position and thickness of Sb2Te3, layer on static reflectivity of the disk (static tester), where Avrami coefficient 'q' in J-M-A rate equation can be derived. The results show that effect of Sb2Te3 layer is essentially to induce crystallization of Ge2Sb2Te5, recording layer from (110) plane of Sb2Te3 crystals. This is due to the fact that the crystallization temperature of Sb2Te3 crystal is 85 degreesC below that of Ge2Sb2Te5 crystal, in addition to a lower lattice mismatch between two crystals. The is in agreement with the J-M-A kinetic analyses that the rate controlling step for amorphous-crystal transformation in disk specimens with Sb2Te3 layer over 15-nm thickness is mainly governed by nucleation with q = 2.53-2.79 > 2.5 in J-M-A equation. Regarding the effects of Sb2Te3 layer on disk properties, the results show that under the 10 nm Ge2Sb2Te5, layer thickness, the Sb2Te3 assisted disks with lower Sb2Te3 layer thickness between 13 and 20 nm show the best combination of reflectivity and modulation. The most important advantage of this process is that the Sb2Te3-assisted disks require no initialization process, because the as-deposited disks can be directly written and erased. (C) 2003 Elsevier B.V. All rights reserved.
On some super fault-tolerant Hamiltonian graphs
(2004-01-30)
Chen, YC
;
Tsai, CH
;
Hsu, LH
;
Tan, JJM
;
資訊工程學系
A k-regular Hamiltonian and Hamiltonian connected graph G is super fault-tolerant Hamiltonian if G remains Hamiltonian after removing at most k - 2 nodes and/or edges and remains Hamiltonian connected after removing at most k - 3 nodes and/or edges. A super fault-tolerant Hamiltonian graph has a certain optimal flavor with respect to the fault-tolerant Hamiltonicity and Hamiltonian connectivity. In this paper, we investigate a construction scheme to construct super fault-tolerant Hamiltonian graphs. In particularly, twisted-cubes, crossed-cubes, and Mobius cubes are all special cases of this construction scheme. Therefore, they are all super fault-tolerant Hamiltonian graphs. (C) 2003 Elsevier Inc. All rights reserved.
Extraction of electrical mechanisms of low-dielectric constant material MSZ for interconnect applications
(2004-01-30)
Chang, TC
;
Yan, ST
;
Liu, R
;
Lin, ZW
;
Aoki, H
In this paper, electrical characterization of low-k dielectric methyl-silsesquiazane (MSZ) is presented. Thermal stress and bias temperature stress (BTS) were utilized to evaluate the impact of Cu penetration on dielectric properties. In the investigation of thermal stress performed by furnace annealing, the leakage mechanism of Al- and Cu-gate MIS capacitors is competed by the decrease of the interfacial states between metal and dielectric and the increase of defects resulted from Cu penetration. Also, the leakage conduction mechanism at high electric field is deduced from Schottky emission in conjunction with space-charge-limited current conduction (SCLC) through BTS methods. (C) 2003 Elsevier B.V. All rights reserved.
Physical and mechanical properties of polyimide/titania hybrid films
(2004-01-30)
Chiang, PC
;
Whang, WT
;
Tsai, MH
;
Wu, SC
;
材料科學與工程學系
Titania-containing polyimide (PI) hybrid films with homogeneous and flexible properties have been fabricated via sol-gel process. Various contents of titania are added to three different PI systems by using acetylacetone to reduce the reaction rate and to prohibit gelation. The thermal, electrical and mechanical properties of the hybrid films will be measured and compared to pure PI. Results indicate that the metal-containing PI possesses lower thermal expansion and resistivity than pure PI. Incorporation of small amount of titania enhances mechanical properties of the hybrid films at both low and elevated temperature. The relationship between the effect of titania concentration, structure and properties will also be discussed. (C) 2003 Elsevier B.V. All rights reserved.
CMP of ultra low-k material porous-polysilazane (PPSZ) for interconnect applications
(2004-01-30)
Chang, TC
;
Tsai, TM
;
Liu, PT
;
Chen, CW
;
Yan, ST
In this article, we investigated the impact of chemical mechanical polishing (CMP) on an ultra low dielectric constant (ultra low-k) material Porous-Polysilazane (PPSZ) with slurries of metal polishing during interconnect manufacture process. Since the CMP processing of metals such as TaN and Cu are inevitable steps for interconnect fabrication, we have utilized two types of slurries (marked as TaN and Cu slurries) to evaluate their effects on the dielectric properties of PPSZ films. Electrical and material analyses have shown surface planarity and dielectric properties of PPSZ films will not be degraded during these metal CMP processes. This indicates that the ultra low-k PPSZ films are promising for inter-level dielectric (ILD) applications in ultra large-scale integrated circuits (ULSI) technology. (C) 2003 Elsevier B.V. All rights reserved.
Moisture resistance and thermal stability of fluorine-incorporation siloxane-based low-dielectric-constant material
(2004-01-30)
Cheng, YL
;
Wang, YL
;
Wu, YL
;
Liu, CP
;
Liu, CW
The low dielectric constant (low-k) of organo-silica-glass (OSG) and fluorine-incorporated OSG (OFSG) materials produced from plasma-enhanced chemical vapor deposition of trimethylsilane are thermally stable to greater than 600 degreesC. FTIR analysis indicates that Si-CH3 bonds and Si-F bonds remain intact to temperatures well above that normally encountered during integrated circuit manufacture, allowing these materials to maintain a low-k value. While OFSG materials proved to have less hydrolytic resistant than their non-fluorinated analogs during high pressure, high temperature water exposure (pressure cooker test), their leakage current was found to be lower than OSG films before and after wafer exposure. The measured properties of OFSG blanket films suggest that this material is sufficiently robust to ensure stability of reliability after the fabrication. (C) 2003 Elsevier B.V. All rights reserved.
Monitor and eliminate the circular defects in HDP-STI deposition through oxynitride/oxide composite liner
(2004-01-30)
Lan, JK
;
Wang, YL
;
Liu, CP
;
Lee, WH
;
Ay, C
This paper investigates. the monitor and elimination methods for the circular defects in high-density-plasma shallow trench isolation (HDP-STI) deposition process. The optical measurement method can monitor the circular defects in early stage. When the thickness of silane-burst film exceeds 7.8 nm, the fit-error can alert the circular defects. The oxynitride/oxide composite liner can eliminate the circular defects. Besides this, the oxynitride/oxide composite liner can also improve the breakdown strength of the STI oxide. The breakdown strength of the STI oxide increases, respectively, 375 and 30% in the wafer center and edge. The uniformity of the STI breakdown strength was reduced from greater than 200% to less than 10% using the composite liner. The traditional N2O plasma treatment for stabilizing the oxynitride film is harmful in the HDP-STI process. The N2O plasma treatment shows the worst circular defect performance. (C) 2003 Elsevier B.V. All rights reserved.
Phase-resolved nonlinear response of a two-dimensional electron gas under femtosecond intersubband excitation
(2004-01-30)
Luo, CW
;
Reimann, K
;
Woerner, M
;
Elsaesser, T
;
Hey, R
Strong electric-field transients resonant to intersubband transitions in n-type modulation-doped GaAs/AlGaAs quantum wells induce coherent Rabi oscillations, which are demonstrated by a phase-resolved measurement of the light emitted by the sample. The time evolution of the intersubband polarization is influenced by Coulomb-mediated many-body effects. The subpicosecond period and the phase of the Rabi oscillations are controlled by the properties of the midinfrared driving pulse.
Investigation of the electrical properties and reliability of amorphous SiCN
(2004-01-30)
Chen, CW
;
Chang, TC
;
Liu, PT
;
Tsai, TM
;
Huang, HC
Amorphous SiCN (a-SiCN) is a candidate for barrier dielectric and has lower dielectric constant (ksimilar to5) relative to the commonly used barrier SiN (ksimilar to7). In this study, we investigate the leaky behavior and barrier characteristics of a-SiCN (k: 4similar to5) doped with different nitrogen concentration. The leaky behavior of a-SiCN is Poole-Frenkel at high electric field. This is similar to SiN. Thermal stability of a-SiCN films is good enough to meet the prescription in back-end-of-line fabrication process. The bias-temperature stress (BTS) test has been conducted on a-SiCN to investigate the barrier ability against copper 15/16penetration. We find that a-SiCN could sustain the stress of electric field up to 4 mV/cm at 150 degreesC. In addition, a-SiCN films with higher nitrogen concentration exhibit better barrier property against copper penetration. The SIMS spectra also have been used to monitor the distributions of copper after different BTS conditions, confirming our inference on leakage mechanism. (C) 2003 Elsevier Science B.V. All rights reserved.
The effectiveness of randomized complete block design
(2004-02-01)
Shieh, G
;
Jan, SL
;
管理科學系
;
Department of Management Science
This paper examines the relative efficiency of randomized complete block design as compared with that of completely randomized design. The most widely used measure of relative efficiency considers only the error variances of the two designs, therefore it does not provide the complete information concerning the sensitivity of the experiment in the final results. We study three alternative criteria related to the sensitivity issue and design planning consideration. The proposed relative measures employ the p-value, Scheffe confidence interval estimation and power of both designs. The distinct feature of this study is the focus on the estimated relative efficiency measures and their relation with the coefficient of partial determination between responses and block effects, given that treatment effects are present in the models. Furthermore, informative visual representations and numerical assessments of various aspects of their properties are also presented.
Thermally activated diffusion observed by in situ reflection high energy electron diffraction intensity monitoring on interrupted SrTiO3 homoepitaxial growth
(2004-02-01)
Wang, TC
;
Juang, JY
;
Wu, KH
;
Uen, TM
;
Gou, YS
The reflection high energy electron diffraction (RHEED) intensity is reported following a quadratic power law dependence on annealing time for interrupted laser ablation-grown strontium titanate films. The activation energy of 1.0eV can further be obtained from the diffusion Arrhenius plot by assuming a direct proportionality between the RHEED intensity and the diffusion length.
Specific interactions in miscible polymer blends of poly(2-hydroxypropyl methacrylate) with polyvinylpyrrolidone
(2004-02-01)
Kuo, SW
;
Shih, CC
;
Shieh, JS
;
Chang, FC
;
應用化學系
The miscibility behaviour and hydrogen-bonding interaction in blends of poly(2-hydroxypropyl methacrylate) (PHPMA) with polyvinylpyrrolidone (PVP) were characterized using differential scanning calorimetry and Fourier-transform infrared spectra. This polymer blend was miscible over the whole composition range and an unusually large positive deviation of T-g from the linearity rule was observed, indicating strong hydrogen bonding between the hydroxyl group of PHPMA and the carbonyl group of PVP. Infrared spectroscopic analysis provided positive evidence for the intra-molecular hydrogen bonding of PHPMA and inter-molecular hydrogen bonding between PHPMA and PVP at various compositions and temperatures. Furthermore, equilibrium constants and enthalpies of self-association and inter-association between functional groups in the blend of PHPMA and PVP were calculated to explain the results. (C) 2004 Society of Chemical Industry.