Browsing by Author "Shih, HC"

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A study on electrochemical metrologies for evaluating the removal selectivity of AlCMP
(1999)
Chiu, SY
;
Hsu, JW
;
Tung, IC
;
Shih, HC
;
Feng, MS
The in-situ electrochemical measurements were performed for the Al and Ti disks in the various slurries under the polishing or static condition. The slurries used contained Al2O3 abrasive, phosphoric acid, citric acid and hydrogen peroxide. The results showed that the addition of H2O2 could help to form an effective passivating layer on the Al surface. Besides, the addition of H2O2 enhanced Al dissolution. The maximum corrosion potential drop between the abraded and non-abraded Al electrodes corresponded to the possible maximum polishing rate of Al. The novel equipment for in-situ galvanic measurements was designed for evaluating the Al/Ti galvanic couple. It was found that Al dissolution could be suppressed in the slurry with the addition of 6 vol% H2O2 at pH 4. As regards the Al/Ti removal selectivity, the polishing with the addition of 6 vol% H2O2 at pH 4 would mitigate the Al dishing, since the polishing and dissolution of Al could be suppressed while those of Ti could be enhanced.
An integrated multichannel selection and dynamic power control scheme for IEEE.802.11 wireless ad hoc networks
(2004)
Chung, J
;
Wang, KC
;
Shih, HC
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose an efficient integrated scheme, E-MCPC, which combines multichannel selection with dynamic power control and is integrated into the IEEE 802.11 power saving mode. Most existing approaches adopted either multichannel selection or power control to improve throughput or to enhance power conservation in wireless ad hoc networks. These approaches only addressed one single issue, either reducing collisions but with inefficient power consumption or enhancing power conservation but with increased collisions. Simulation results have shown that our E-MCPC can achieve 1.2 times and 30% higher throughput, and 2.5 times and 2 times better power conservation compared to the IEEE 802.11 and MCPC, respectively, in a wireless ad hoc dense network with high traffic load.
Electrochemical behavior of copper chemical mechanical polishing in KIO3 slurry
(2002-03-01)
Hsu, JW
;
Chiu, SY
;
Tsai, MS
;
Dai, BT
;
Feng, MS
The electrochemical behavior of polishing copper with colloidal silica abrasive slurry formulated with KIO3 oxidizer has been investigated. For planarization of the surface morphology, the control of the surface passivation of Cu is critical during polishing. KIO3 is not only all oxidizer but also a passivator for copper in an acidic slurry by forming a CuI layer on the surface. With alkaline slurry, Cu2O is the primary corrosion product on the Cu surface. The copper corrosion rate and removal rate can be decreased dramatically with increasing slurry pH. The low corrosion resistance or high corrosion susceptibility of Cu as determined by electrochemical measurements is the basis for the high removal rates. The copper removal rate is reduced from 4600 to 650 Angstrom/min when the slurry pH is increased from 2 to 5: and the copper removal rate levels off atpH 7 with a steady-state removal rate of 200 Angstrom/min, (C) 2002 American Vacuum Society.
Electron field emission from fluorinated amorphous carbon nanoparticles on porous alumina
(2003-12-15)
Lai, SH
;
Huang, KP
;
Pan, YM
;
Chen, YL
;
Chan, LH
The fluorinated amorphous carbon nanoparticles (a-C:F NPs) films have been prepared on a porous alumina at a lower temperature of similar to100 degreesC by an ECR-CVD system with a mixture of CF4, C2H2 and Ar as precursors. The morphology of a-C:F NPs films was verified by FESEM. The microstructure and chemical bonding nature of the a-C:F NPs films were investigated by Raman spectroscopy and XPS, respectively. The fluorinated samples need a lower field (similar to2.25 V/mum for 10.6% F a-C:F NPs films) to emit the electron than unfluorinated ones. The excellent field-emission properties of a-C:F NPs films are due to the effect of the shape, fluorine doping and dangling bonds. (C) 2003 Elsevier B.V. All rights reserved.
Field-emission properties of aligned carbon nanotubes
(2000-09-15)
Hong, WK
;
Shih, HC
;
Tsai, SH
;
Shu, CT
;
Tarntair, FG
Dense, well-separated, and aligned carbon nanotubes have been prepared via bias-enhanced microwave plasma chemical vapor deposition. The turn-on fields defined at the emission current density of 10 mu A/cm(2) are about 3.35 V/mu m, 2.54 V/mu m, and 3.54V/mu m, for the immersion times in PdCl2 of 1 min, 20 min, and 40 min,respectively. The corresponding emission current densities are about 0.97 mA/cm(2), 4.5 mA/cm(2), and 0.44 mA/cm(2) at the electric field of 5 V/mu m. The higher emission current obtained from the aligned carbon nanotubes for the immersion time of 20 min is ascribed to the denser and sharper nanotubes formed in this condition.
Growth mechanism of laser annealing of nickel-induced lateral crystallized silicon films
(2006-01-01)
Hu, GR
;
Wu, YS
;
Chao, CW
;
Shih, HC
;
材料科學與工程學系
The growth mechanism of a hybrid process to crystallize amorphous silicon (a-Si) film was studied. In the process, a-Si was first converted to polycrystalline silicon (poly-Si) using Ni-metal-induced lateral crystallization (NILC), and then annealed with an excimer laser (ELA). Two regions based on different crystallization mechanisms were found on these NILC-ELA films: (A) a-Si melting region, and (13) a-Si/poly-Si melting region. In the a-Si melting region, the sizes and shapes of the needle Si grains were similar to those of NILC poly-Si. In the a-Si/poly-Si melting region, the shapes and sizes of poly-Si grains were quite different from those of NILC needlelike grains. Two crystallization regimes were found in the a-Si/poly-Si melting region: (1) geometrical coalescence regime and (2) complete melting regime. In the geometrical coalescence regime, the width of grains dramatically increased to 600 nm due to the geometrical coalescence of Si needle grains. However, in the complete melting regime, the NILC Si films melted completely. Small poly-Si grains were formed by homogeneous nucleation and growth.
Interfacial mechanism studies of electroless plated Cu films on a-Ta : N layers catalyzed by PIII
(2002-05-01)
Lin, JH
;
Lee, TL
;
Hsieh, WJ
;
Lin, CC
;
Kou, CS
This study evaluated the interface reaction and crystallography of the electroless plated copper film (similar to0.2 mum thick) catalyzed by plasma immersion ion implanted (PIII) Pd on the 150-Angstrom-thick amorphous tantalum nitride (a-Ta:N) barrier layer. The copper plated specimens were annealed at various temperatures in an ambient atmosphere of 90% nitrogen + 10% hydrogen mixed gases. Sheet resistivity, Auger electron spectroscopy (AES) analyses showed that the PIII Pd atoms were diffused into the copper layer from the interface of a-Ta:N and copper layers after 500 degreesC annealing for 1 h. Results based on x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) showed a phase transformation from a-Ta:N into crystallized Ta2N phase at annealing. The Cu(111) texture was strengthened at 300degreesC annealing for I h because of the relaxation of the residual stress and recovery of the copper film. The texture was reduced at the 500 degreesC annealing for I h because of the copper grain growth. The adhesion strength of copper films on a-Ta:N barrier layer was enhanced by the annealing because of the interdiffusion of copper layer, Pd clusters and a-Ta:N barrier layer. The annealing temperatures lower than 300 degreesC help to reduce the electric resistivity of copper film, to strengthen the Cu(111) preferred orientation. and to enhance the adhesion strength of copper films on a-Ta:N layer. However, the specimen annealed at 500 'C manifested the diffusion of Pd atoms into the copper film and resulted in a significant increase of the electric resistivity of copper film. (C) 2002 American Vacuum Society.
Role of extrinsic atoms on the morphology and field emission properties of carbon nanotubes
(2003-06-16)
Chan, LH
;
Hong, KH
;
Xiao, DQ
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Hsieh, WJ
;
Lai, SH
Extrinsic atoms were doped into multiwalled carbon nanotubes (MWCNTs) using microwave plasma-enhanced chemical vapor deposition. Doped nitrogen atoms alter the original parallel graphenes into highly curved ones including some fullerene-like structures. Doped nitrogen atoms could replace carbon atoms in MWCNTs and therefore increase the electronic density that enhances the electron field emission properties. On the other hand, the incorporation of boron into the carbon network apparently increases the concentration of electron holes that become electron traps and eventually impedes the electron field emission properties. Fowler-Nordheim plots show two different slopes in the curve, indicating that the mechanism of field emission is changed from low to high bias voltages. beta values could be increased by an amount of 42% under low bias voltages and 60% under high bias voltages in the N-doped MWCNTs, but decreased by an amount of 8% under low bias region and 68% under high bias voltage in the B-doped MWCNTs. (C) 2003 American Institute of Physics.
Simultaneous etching of polysilicon materials with different doping types by low-damage transformer-coupled plasma technique
(2002-09-01)
Hung, CC
;
Lin, HC
;
Wang, MF
;
Huang, TY
;
Shih, HC
The feasibility of simultaneously etching n(+), p(+), and undoped polysilicon (poly-Si) materials by a commercial transformer coupled plasma (TCP) reactor has been investigated in this study. Response surface methodology (RSM) was used to optimize process parameters including pressure, TCP source power, bias power, and Cl-2/HBr flow on the main etch step. Quantitative relationships between etching performance and process parameters were established. Our results indicate that there exists a process parameter window that meets the requirements of etching polysilicon with different doping types simultaneously. High etch rate, superior uniformity, good end point detection (EPD) characteristics and profile control can be simultaneously obtained with the optimized recipe, irrespective of the doping types. Furthermore, only minor plasma-induced damage is detected as monitored from antenna transistors' charge-to-breakdown (Q(bd)), threshold voltage and charge pumping current. (C) 2002 Elsevier Science B.V. All rights reserved.
Structure and electrical studies of fluorinated amorphous carbon films prepared by electron cyclotron resonance/chemical-vapor deposition
(2003-06-01)
Huang, KP
;
Lin, P
;
Shih, HC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Fluorinated amorphous carbon (a-C:F) films of high fluorine content were prepared by radio-frequency (RF) bias assisted electron cyclotron resonance/chemical-vapor deposition (ECR-CVD) with a variable fluorine-to-carbon (F/C) ratio of the feed gases. The films were characterized by X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS) and transmission electron microscopy (TEM). A low dielectric constant of around 1.5 and high dielectric strength beyond 35 MV/cm were obtained under the as-deposited and annealed conditions, respectively. The measured huge current surge and electrical conductivity of the films were discussed on the basis of the nanovoids and sp(2)/Sp(3) bonding fractions as derived from the above characterizations. [DOI: 10.1143/JJAP.42.3598].
Structures and properties of fluorinated amorphous carbon films
(2004-07-01)
Huang, KP
;
Lin, P
;
Shih, HC
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF4) and acetylene (C2H2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF4/(CF4+C2H2). The samples were annealed at 300 degreesC for 30 min. in a N-2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF4 flow ratio (R=0.97) produced more sp(3) linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 mus and an energy gap of similar to2.75 eV were observed in both the as-deposited and after annealing conditions. The short carriers lifetime in the a-C:F film made the photoluminescence peak blueshift. The annealing changed both the structure and composition of the a-C:F film. The type of fluorocarbon bond and electronic structure characterized the mechanical and physical properties of a-C:F film. (C) 2004 American Institute of Physics.
The microstructure of As precipitates in Si delta-doped GaAs grown by low-temperature molecular beam epitaxy
(1997-11-01)
Hsieh, LZ
;
Huang, JH
;
Su, ZA
;
Guo, XJ
;
Shih, HC
The structure relationship of the As precipitates found in post-annealed Si delta-doped GaAs layers grown by low-temperature molecular beam epitaxy is elucidated by transmission electron microscopy (TEM). There are six extra spots around the diffraction pattern of GaAs for a sample annealed at 700 degrees C. The As precipitates and GaAs matrix are found to be semicoherent with the hexagonal [-1-21](As) parallel to the cubic [110](GaAs). Because of the different lattice constants and Bravias lattices between GaAs and As precipitates, these extra spots are formed by double-diffraction effects. The high-resolution TEM images show two types of Moire fringes. One is the parallel Moire pattern and the other is the rotation Moire pattern. The relative positions of the extra spots in the diffraction pattern correspond to the orientation and spacing of Moire fringes.
The microstructure of As precipitates in Si delta-doped GaAs grown by low-temperature molecular beam epitaxy
(1997-11-01)
Hsieh, LZ
;
Huang, JH
;
Su, ZA
;
Guo, XJ
;
Shih, HC
The structure relationship of the As precipitates found in post-annealed Si delta-doped GaAs layers grown by low-temperature molecular beam epitaxy is elucidated by transmission electron microscopy (TEM). There are six extra spots around the diffraction pattern of GaAs for a sample annealed at 700 degrees C. The As precipitates and GaAs matrix are found to be semicoherent with the hexagonal [-1-21](As) parallel to the cubic [110](GaAs). Because of the different lattice constants and Bravias lattices between GaAs and As precipitates, these extra spots are formed by double-diffraction effects. The high-resolution TEM images show two types of Moire fringes. One is the parallel Moire pattern and the other is the rotation Moire pattern. The relative positions of the extra spots in the diffraction pattern correspond to the orientation and spacing of Moire fringes.
The removal selectivity of titanium and aluminum in chemical mechanical planarization
(2002-03-01)
Hsu, JW
;
Chiu, SY
;
Wang, YL
;
Dai, BT
;
Tsai, MS
The removal selectivity control of aluminum and titanium metal barrier during aluminum chemical mechanical polishing in the Damascene process is known to be critical for surface planarity without metal dishing and dielectric erosion. Unfortunately, the electrochemical behaviors of aluminum and titanium are dissimilar, as one may expect. In this study, in situ electrochemical impedance spectroscopy was carried out to investigate the influences of H(2)O(2) concentration, slurry pH, and metal oxide formation through the passivation on aluminum and titanium. As H(2)O(2) concentration increases, the measured impedance of aluminum and titanium decreases, or the oxidation rates of these two metals are enhanced upon increasing the oxidizer concentration. As the slurry pH increases, the removal rate of polished titanium increases, but it decreases for polished aluminum. The removal rate of titanium was limited to its oxidation rate and aluminum was limited to its oxide dissolution rate. (C) 2002 The Electrochemical Society.
Trench gap-tilling copper by ion beam sputter deposition
(2006-05-10)
Han, S
;
Lee, TL
;
Yang, CJ
;
Shih, HC
;
材料科學與工程學系
The ion beam sputter deposition (IBSD) and electroless plating techniques have been combined to achieve the precipitation of Cu onto an amorphous (a)-TaN diffusion barrier layer in order to accomplish the ultralarge-scale-integrated interconnect metallization. The copper-filled specimens were annealed at various temperatures in a reduced atmosphere. The preferred orientation was analyzed by X-ray diffraction, and field emission scanning electron microscopy was used to elucidate the growth mechanism of the trench-filled electroless deposited Cu film on the Cu seeded layer by IBSD. The Cu(1 1 1) texture was strengthened by annealing at 300 degrees C for 1 h. The surface roughness increased notably with increasing annealing temperature. The electrical resistivity of the as-deposited copper film (3.05 mu Omega cm) decreased with increasing annealing temperature. The major contribution of this study is to successfully combine the techniques of IBSD and electroless plating for the Cu gap-filling of submicron trenches with an excellent step coverage. (c) 2006 Published by Elsevier B.V.