Browsing by Issue Date, starting with "2006-11-25"

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Field emission characteristics of chromium carbide capped carbon nanotips
(2006-11-25)
Hsu, C. H.
;
Chen, C. F.
;
Lo, H. C.
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this study, field emission characteristics of two carbon based nanomaterials, carbon nanotips and chromium carbide capped carbon nanotips, were discussed. Both of these materials were synthesized by bias-assisted microwave plasma chemical vapor deposition with hydrogen and methane as reactants. Ultra-sharpness of the carbon nanotips and the composite structure of chromium carbide capped carbon nanotips have shown unique structural and electrical properties. I-V measurements were carried out to investigate the field emission characteristics. The chromium carbide capped carbon nanotips showed superior field emission stability compared to carbon nanotips under constant current emission. (c) 2006 Elsevier B.V. All rights reserved.
High-performance polycrystalline silicon thin-film transistors with oxidenitride-oxide gate dielectric and multiple nanowire channels
(2006-11-25)
Chen, Shih-Ching
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Chang, Ting-Chang
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Liu, Po-Tsun
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Wu, Y. C.
;
Tsai, C. C.
This work presents a method to enhance the performance of polycrystalline silicon thin film transistors (poly-Si TFTs) by using an oxide-nitride-oxide (ONO) gate dielectric and the multiple nanowire channels structure. Experimental results indicate that the performance of the device was enhanced by using the ONO multilayer, because the ONO gate dielectric constant is increased compared to the conventional oxide gate dielectric. Additionally, the TFTs with a ten nanowire channel structure (NW-TFTs) have superior electrical characteristics compared to other TFTs. This is because a structure with more corners and a shorter radius has better gate control due to the corner effect. (c) 2006 Elsevier B.V. All rights reserved.
Statistical study on the states in the low-temperature poly-silicon films with thin film transistors
(2006-11-25)
Huang, Shih-Che
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Chou, Yen-Pang
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Tai, Ya-Hsiang
;
光電工程學系
;
顯示科技研究所
Laser recrystallized low temperature poly-silicon films have attracted attention for their applications in thin-film transistors (TFTs), which are widely used in active matrix displays. The electrical characteristics of the poly-silicon film may vary because of its grain boundaries. In this work, the variation is statistically studied with respect to the threshold voltage and mobility of the TFTs. The threshold voltage and mobility of many closely-located TFTs are measured. These two parameters correspond to the deep states and tail states of the poly-silicon film, respectively. The mutual difference of two threshold voltages exhibits the distribution in a Gaussian-Lorentzian cross product form. On the other hand, the mutual difference of two mobility exhibits the distribution of Lorentzian function. This result directly reflects the local fluctuations and the spatial trends of the deep and tail states in a poly-silicon film. (c) 2006 Elsevier B.V. All rights reserved.
Study on electrical degradation of p-type low-temperature polycrystalline silicon thin film transistors with C-V measurement analysis
(2006-11-25)
Huang, Shih-Che
;
Kao, Yu-Han
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Tai, Ya-Hsiang
;
光電工程學系
;
顯示科技研究所
Laser recrystallized low-temperature poly-silicon (LTPS) films have attracted attention for their application in thin-film transistors (TFTs), which are widely used in active matrix display. However, the degradation behavior of p-type LTPS TFTs is not quite clarified yet. In this paper, the instability mechanisms of p-channel LTPS TFTs under DC bias stress have been investigated. From the IV transfer curves, it was observed that LTPS TFT's mobility increases after stress at some bias conditions. This degradation is most likely caused by interface traps between the poly-Si thin film and the gate insulator, as well as the damaged junction of the drain from stress. In this work, the assumption is examined via C-V measurement. It is found that the C-GD curves of the stressed TFT slightly increase for the gate voltage smaller than the flat band voltage V-FB. However, the C-Gs curves of the stressed device are almost the same as those before stress. By employing simulation, it is found that the degradation of p-type TFTs under this stress condition is mainly caused by the trapped charges at the interface between the gate and the drain region, which is generated by the high voltage difference applied during DC bias stress. (c) 2006 Elsevier B.V. All rights reserved.
Effect of alumina doping on structural, electrical, and optical properties of sputtered ZnO thin films
(2006-11-25)
Bai, S. N.
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Tseng, T. Y.
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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 systematic study of the influence of alumina (Al2O3) doping on the optical, electrical, and structural characteristics of sputtered ZnO thin films is reported in this study. The ZnO thin films were prepared on 1737F Coming glass substrates by R.F. magnetron sputtering from a ZnO target mixed with Al2O3 of 0-4 wt.%. X-ray diffraction (XRD) analysis demonstrates that the ZnO thin films with Al2O3 of 0-4 wt.% have a highly (002) preferred orientation with only one intense diffraction peak with a full width at half maximum (FWEM) less than 0.5 degrees. The electrical properties of the Al2O3-doped ZnO thin films appear to be strongly dependent on the Al2O3 concentration. The resistivity of the films decreases from 74 Omega(.)cm to 2.2 x 10(-3) Omega(.)cm as the Al2O3 content increases from 0 to 4 wt.%. The optical transmittance of the Al2O3-doped ZnO thin films is studied as a function of wavelength in the range 200-800 nm. It exhibits high transparency in the visible-NIR wavelength region with some interference fringes and sharp ultraviolet absorption edges. The optical bandgap of the Al2O3-doped ZnO thin films show a short-wavelength shift with increasing of Al2O3 content. (c) 2006 Elsevier B.V. All rights reserved.
Synthesis and thermal decomposition of Zn(tda)H2O [tda = S(CH2COO)(2)(2-)]
(2006-11-27)
Wu, Ming-Cheng
;
Lee, Chi-Shen
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應用化學系
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應用化學系分子科學碩博班
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Department of Applied Chemistry
A novel two-dimensional coordination polymer Zn(tda)H2O [tda = S(CH2COO)(2)(2-)] was synthesized under hydrothermal conditions. The compound crystallized in monoclinic space group P2(1) with a = 16.4154(17) angstrom, b = 5.2133(6) angstrom, c = 16.4210(17) angstrom, beta = 114.165(2)degrees, V = 1282.1(2) angstrom(3), and Z = 8. The structure features two-dimensional, noncentrosymmetric networks with a pseudohexagonal network of Zn2+ coordinated by tda and water molecules. Zn(tda)H2O decomposed at T > 300 degrees C to form a ZnO sponge with a surface area similar to 40 m(2)/g, which makes it an attractive precursor for nanoporous ZnO.
30 nm resolution x-ray imaging at 8 keV using third order diffraction of a zone plate lens objective in a transmission microscope
(2006-11-27)
Yin, Gung-Chian
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Song, Yen-Fang
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Tang, Mau-Tsu
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Chen, Fu-Rong
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Liang, Keng S.
A hard x-ray transmission microscope with 30 nm spatial resolution has been developed employing the third diffraction order of a zone plate objective. The microscope utilizes a capillary type condenser with suitable surface figure to generate a hollow cone illumination which is matched in illumination range to the numerical aperture of the third order diffraction of a zone plate with an outmost zone width of 50 nm. Using a test sample of a 150 nm thick gold spoke pattern with finest half-pitch of 30 nm, the authors obtained x-ray images with 30 nm resolution at 8 keV x-ray energy. (c) 2006 American Institute of Physics.
Chemical vapour deposition of oriented diamond nanocrystallites by a bias-enhanced nucleation method
(2006-11-28)
Yan, Jhih-Kun
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Chang, Li
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材料科學與工程學系
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Department of Materials Science and Engineering
A microwave plasma chemical vapour deposition (MPCVD) system has been used to deposit nanometre-sized single-crystalline diamonds on 1 x 1 cm(2) Si(100) substrates. The distribution of deposited diamonds has good uniformity over the whole Si substrate surface by using a dome-shaped Mo anode which allows the application of bias-enhanced nucleation. The morphology and crystallinity of the deposits on Si were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with electron diffraction and lattice images. SEM and TEM observations show that oriented diamond nuclei as single crystals with facets can form on self-formed Si cones through epitaxial SiC within a short bias period. After a longer bias time, it has been observed that polycrystalline diamonds formed as a result of secondary nucleation.
选择内部编码的预测模式的方法及其装置
(2006-11-29)
郑朝钟
;
张添烜
;
蔡志侃
一种选择内部编码的预测模式的方法包含计算多个预测模式中第一族群中的预测模式的误差值，该第一族群包含两个其预测方向的夹角为最大的该预测模式；计算第二族群中的预测模式的误差值，该第二族群的预测模式是指其预测方向靠近该第一族群中误差值较小者的预测方向两侧的预测模式；计算第三族群中的预测模式的误差值，该第三族群的预测模式是指其预测方向相邻于该第二族群中误差值较小者的预测方向的预测模式；计算多个预测模式中的直流预测模式的误差值；以及选择已计算过误差值的预测模式中误差值最小者作为将子块编码的预测模式。
应用于视频编码/解码的解块滤波方法及其装置
(2006-11-29)
郑朝钟
;
张添烜
;
林天虹
一种应用于视频编码/解码的解块滤波方法，其步骤包含依据一解块方向，依序读取相邻于一垂直边界的该子块，并对该垂直边界进行该解块处理；将一目前子块的像素数据进行转置；对该目前子块的一平行边界进行该解块处理，相邻于该平行边界的另一子块的像素数据则转置后输出；依序储存多个该目前子块；以及在该目前宏块的解块处理完成后，将该多个目前子块的像素数据转置输出。
Laser-ablated fiber devices and method of manufacturing the same
(2006-11-30)
Chi, Sien
;
Chen, Nan-Kuang
A manufacturing method of a laser-ablated fiber device is proposed. The fiber cladding is removed by laser beam until the evanescent field is accessed. The depth of ablation is controlled by measuring the distance between the interference fringes of the laser. The effective interaction length is tuned by varying the radius of curvature of the fiber. The ablated fibers are mated to act as a fiber coupler. Subsequently, the interaction region is fused or fused-tapered to make a fiber coupler, an add/drop multiplexer, a fiber filter, etc.
Method of symbol detection for MIMO dual-signaling uplink CDMA systems
(2006-11-30)
Ho, Chung-Lien
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Wu, Jwo-Yuh
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Lee, Ta-Sung
The invention provides a block V-BLAST detection algorithm for a general multi-input multi-output CDMA system over the frequency-selective channels, in which each user's data stream can be either orthogonal space-time block encoded for transmit diversity or spatially multiplexed for high spectral efficiency according to the channel conditions. For such the considered dual-signaling system, the receiver could suffer from the large dimension data processing. A two-stage group V-BLAST detection algorithm is thus proposed to further reduce the computational complexity.
ESD-protection design with extra low-leakage-current diode string for RF circuits in SiGeBiCMOS process
(2006-12-01)
Ker, Ming-Dou
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Hsiao, Yuan-Wen
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Wu, Woei-Lin
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電機學院
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College of Electrical and Computer Engineering
Two low-leakage resistor-shunted diode strings Eire developed for use as power clamps in silicon-germanium (SiGe) BiCMOS technology. The resistors are used to bias the deep N-wells, significantly reducing the leakage current from the diode string. A methodology for selecting the values of the bias resistors is presented. For further reduction of the leakage current, an alternate design is presented: the resistor-shunted trigger bipolar power clamp. The power-clamp circuits presented herein may be used in cooperation with small double diodes at the I/O pins to achieve whole-chip electrostatic-discharge protection for RF ICs in SiGe processes.
Process and characteristics of fully silicided source/drain (FSD) thin-film transistors
(2006-12-01)
Lin, Chia-Pin
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Hsiao, Yi-Hsuan
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Tsui, Bing-Yue
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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
In this paper, high-performance fully silicided source/drain (FSD) thin-film transistors (TFTs) with FSD and ultrashort source/drain extension (SDE) fabricated by the implantto-silicide (ITS) technique are studied thoroughly. Using the ITS technique, not only the implantation damage but also the silicide spiking is avoided so that the thermal budget can be decreased obviously. The offstate current (I-off) of the FSD TFTs is equal to (n-channel) or smaller than (p-channel) that of the conventional TFTs. At onstate, due to the FSD and the SDE structure, the parasitic resistance of the S/D region and the carrier-injection resistance between silicide and channel are reduced. Therefore, superior onstate/offstate current ratio can be obtained. The influences of annealing temperature and time are also examined in this paper. A 600 degrees C/30-s rapid thermal annealing is sufficient to diffuse and activate dopants and, then, fabricate high-performance FSD TFTs. Excellent short-channel behavior of the FSD TFT is also confirmed. To conclude, the high-performance FSD TFT with low parasitic resistance fabricated by low-thermal-budget process is very promising for active-matrix liquid-crystal display, active-matrix organic light-emitting-diode display, and system-on-panel applications.
Optical transfer functions for specific-shaped apertures generated by illumination with a rectangular light pipe
(2006-12-01)
Cheng, Chu-Ming
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Chern, Jyh-Long
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光電工程學系
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Department of Photonics
We investigated the pupil functions of specific-shaped apertures generated by Lambertian illumination with a rectangular light pipe to derive the corresponding optical transfer functions (OTFs) in aberration-free and defocused optical systems. The semianalytical results indicate that the curves of the OTF of the optical system vary with the form of the shaped apertures that are generated by illumination with different geometric structures of light pipes and light sources. It was found that the OTF values of even-peak frequencies decrease when the Lambertian light source decreases. If there are a total of n X n individual apertures within a pupil, then n near-periodical peaks will appear on the OTF curve. It is evident that the values of the OTF remain almost unchanged even when the lengths of the light pipes are different. Furthermore, the geometric structure of the light pipe does not affect the resolution limit of the optical system, and under the condition of a larger defocused coefficient omega(20), the results of the defocused system can coincide with those of the aberration-free systems. (c) 2006 Optical Society of America.
Parallel implementation of a three-dimensional electrostatic PIC-MCC method using an unstructured tetrahedral mesh
(2006-12-01)
Wu, J. -S.
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Hsu, K. -H.
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機械工程學系
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Department of Mechanical Engineering
A parallel three-dimensional electrostatic particle-in-cell Monte Carlo Collision (PIC-MCC) code using an unstructured tetrahedral mesh is developed and validated in this paper. Poisson's equation is discretized by a nodal finite element method using a linear interpolation function. Charged-particle motion is traced cell by Cell using a leap-frog method and the Boris scheme. Code is validated using quasi-one-dimensional radiofrequency gas discharge by observing the bi-Maxwellian electron energy probability distribution function at low pressure. Parallel performance of the PIC code is tested using a three-dimensional radiofrequency gas discharge on a PC-cluster system. Results show that parallel efficiency of 83% can be achieved at 32 processors with dynamic domain decomposition.
New Cu/Mo/Ge/Pd ohmic contacts on highly doped n-GaAs for InGaP/GaAs heterojunction bipolar transistors
(2006-12-01)
Chang, Chun-Wei
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Hseh, Tung-Ling
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Chang, Edward Yi
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材料科學與工程學系
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Department of Materials Science and Engineering
The feasibility of using novel Cu/Mo/Ge/Pd ohmic contacts on n+-GaAs for heterojunction bipolar transistors (HBTs) is investigated. The electrical and material characteristics of the Cu/Mo/Ge/Pd/n(+)-GaAs structure were studied. After thermal annealing at 350 degrees C, the specific contact resistances of the copper ohmic contacts Cu/Mo/Ge/Pd were measured to be 2.8 x 10(-7) Omega cm(2). Judging from the data of sheet resistance, X-ray diffraction analysis, Auger electron spectroscopy, and transmission electron microscopy, the Cu/Mo/Ge/Pd contact structure was very stable after annealing at 350 degrees C. However, after 400 degrees C annealing, the reaction of copper with the underneath layers started to occur and formed MoGe2, Cu3Ga and Ge3CU phases. An InGaP/GaAs HBT with C'u/Mo/Ge/Pd contact metals was fabricated and compared with an HBT fabricated with traditional Au/Ni/Ge/Au contact metals. These two kinds of HBTs showed similar device characteristics. After reaching thermal stability and per-forming a high current-accelerated stress test at a current density of 120 kA/cm(2) for 24h, the device with the Cu/Mo/Ge/Pd ohmic contacts still exhibits excellent electrical characteristics.
Comparison on the sensitivity of fiber-optic SONET OC-48PIN-TIAs measured by using synchronous modulation intermixing technique and bit error rate tester
(2006-12-01)
Liao, Yu-Sheng
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Lin, Gong-Ru
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光電工程學系
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Department of Photonics
A novel synchronous modulation and intermixing (SMIM) technique is presented to measure the sensitivity and evaluate the bit error rate (BER) of p-i-n photodiode receivers with transimpedance amplifiers (PIN-TIAs) without using any BER tester (BERT). When using the SMIM technique, the premier receiving measurement performance from the data rates of the synchronous optical network OC-3 to OC-48 was demonstrated. For general TO-46 packaged PIN-TIAs; a minimum intermixed voltage of 12.5 mV obtained by the SMIM method is equivalent to a sensitivity of -31 dBm at a requested BER of < 10(-10) determined by BERT. The relationship between the monitoring voltage and the BER of the optical pattern received by the PIN-TIA and limited amplifier is estimated. The error of the measured voltage is 0.28 mV, which corresponds to the error sensitivity of 0.09 dB. This would show the accuracy of the simplified and low-cost SMIM technique for in situ diagnostics on a mass-production line.
Study of traps in polydiacetylene based devices using TSC technique
(2006-12-01)
Renaud, C.
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Huang, C. H.
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Zemmouri, M.
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Le Rendu, P.
;
Nguyen, T. P.
Trap parameters in poly(1-(3,4-difluorophenyl)-2-(4-pentylcyclohexylphenyl)acetylene) (PDPA-2F) based devices have been investigated by using the thermally stimulated current (TSC) technique. The device structure is ITO-PEDOT-(PDPA-2F)-M, where M stands for the cathode metal (Al, Ca/Al, and Au). The results reveal at least three TSC peaks in devices denoted as peaks A, B and C. Comparing trap parameters in ITO-PEDOT-(PDPA-2F)-Au hole-only device and ITO-PEDOT-(PDPA-2F)-Ca Al (Al) bipolar devices, we assigned A and B trap types to hole-like traps and C type traps to electron-like traps. The trap densities are in the range of 10(15)-10(17) cm(-3) and the trap levels are 0.12 eV (A type traps), 0.36 eV (B type traps), and 0.25 eV (C type traps).
A semicylindrical capacitive sensor with interface circuit used for flow rate measurement
(2006-12-01)
Chiang, Cheng-Ta
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Huang, Yu-Chung
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a semicylindrical capacitive sensor with an interface circuit used for flow rate measurement is proposed. The numerical analysis method to calculate the capacitance of the semicylindrical capacitive sensor is analyzed and discussed. The picofarad-range capacitive variation of the semicylindrical capacitive sensor can be detected and converted into voltage variation by the interface circuit. Besides, the interface circuit is compact enough to simplify the circuit complexity and could be easily implemented for flow rate measurement. All the functions of the capacitive sensing method of the semicylindrical capacitive sensor used for flow rate measurement are proved successfully through HSPICE simulation. Measurement results have successfully confirmed the correct functions and performance of the semicylindrical capacitive sensor with an interface circuit used for flow rate measurement, which ranges from 0.136 to 4.746 L/min, on the liquid crystal display panel coating machine.