Browsing by Author "Wu, YC"

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A dual-gate-controlled single-electron transistor using self-aligned polysilicon sidewall spacer gates on silicon-on-insulator nanowire
(2004-03-01)
Hu, SF
;
Wu, YC
;
Sung, CL
;
Chang, CY
;
Huang, TY
A dual-gate-controlled single-electron transistor was fabricated by using self-aligned polysilicon sidewall spacer gates on a silicon-on-insulator nanowire. The quantum dot formed by the electric field effect of the dual-gate structure was miniaturized to smaller than the state-of-the-art feature size, through a combination of electron beam lithography, oxidation, and polysilicon sidewall spacer gate formation processes. The device shows typical MOSFET I-V characteristics at room temperature. However, the Coulomb gap and Coulomb oscillations are clearly observed at 4 K.
A silicon nanowire with a Coulomb blockade effect at room temperature
(2002-05-17)
Hu, SF
;
Wong, WZ
;
Liu, SS
;
Wu, YC
;
Sung, CL
An extremely narrow and thin silicon wire has been fabricated on a silicon-on-insulator wafer (see Figure). The room-temperature Coulomb blockade effects as well as the influence of a capacitively coupled gate on the transport properties of this conducting silicon quantum wire are studied. The results obtained are encouraging for the application of such wires in single-electron transistors.
Application of FIDF to the detection of unstable behaviors in compression systems
(2000)
Liang, YW
;
Liaw, DC
;
Wu, YC
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電控工程研究所
;
Institute of Electrical and Control Engineering
Issues concerning the detection of surge and rotating stall in a compression system are studied in this paper. It is observed that the plenum pressure rise and mass flow rate of a compression system exhibit abrupt change due to the appearance of surge or rotating stall, while those of it's linearized model do not. With this observation, a linear-based fault identification filter (FIDF) design technique is proposed to detect these two instabilities. This is achieved by treating the difference between the output of the compression system and that of its linearized model at an unstalled operating point as a fault vector and then investigating the effect of the fault on the designed FIDF. Simulation results for Moore and Greitzer's compression model [14] are given to demonstrate the effectiveness of the proposed scheme. The study may provide a means of detecting the occurrence of unstable phenomena at the onset so that a corrective action can be made.
Characteristics of fluorinated amorphous carbon films and implementation of 0.15 mu m Cu/a-C : F damascene interconnection
(2001-05-01)
Shieh, JM
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Suen, SC
;
Tsai, KC
;
Dai, BT
;
Wu, YC
Fluorinated amorphous carbon films (a-C:F) deposited by plasma enhanced chemical vapor deposition with low dielectric constant (K similar to2.3), thermal stability (higher than 400 degreesC) and acceptable adhesion to a cap layer such as SiOF or SiO2 were obtained by varying the range of content ratios between carbon and fluorine, the rf power, the process pressure and the base temperature. Standard x-ray photoelectron spectroscopy and thermal desorption spectroscopy metrologies were employed to characterize the deposited a-C:F films. The damascene pattern with 0.15 mum and an etching selectivity of more than 50 (a-C:F/SiOF, SiO2) was implemented by a mixture of etching gases of N-2+O-2. The bias power, rf power and gas hows were incorporated to optimize the etching recipe for achieving a damascene profile with a high aspect ratio. The scanning electron microscope results showed that a better etch profile can be obtained at higher bias power. In our damascene architecture, the etching stop layer or hard mask of both SiOF and SiO2 was studied. The SiOF, providing a lower dielectric constant than SiO2, would especially reduce the entire effective dielectric constant. Furthermore, we integrated electroplated copper into trenches or vias as small as 0.15 mum, with aspect ratio of 6. (C) 2001 American Vacuum Society.
Effects of channel width and NH3 plasma passivation on electrical characteristics of polysilicon thin-film transistors by pattern-dependent metal-induced lateral crystallization
(2005)
Wu, YC
;
Chang, TC
;
Chou, CW
;
Wu, YC
;
Liu, PT
This work studied the effects of channel width and NH3 plasma passivation on the electrical characteristics of a series of pattern-dependent metal-induced lateral crystallization (PDMILC) polysilicon thin-film transistors (poly-Si TFTs). The performance of PDMILC TFTs improves as each channel width decreasing. Further, PDMILC TFTs with NH3 plasma passivation outperforms without such passivation, resulting from the effective hydrogen passivation of the grain-boundary dangling bonds, and the pile-up of nitrogen at the SiO2/poly-Si interface. In particular, the electrical characteristics of a nanoscale TFT with ten 67 nm wide split channels (M10) are superior to those of other TFTs. The former includes a higher field effect mobility of 84.63 cm(2)/V s, a higher ON/OFF current ratio (> 10(6)), a steeper subthreshold slope (SS) of 230 mV/decade, and an absence of drain-induced barrier lowering (DIBL). These findings originate from the fact that the active channels of the M10 TFT have exhibit the most poly-Si grain enhanced to reduce the grain boundary defects and the best NH3 plasma passivation. Both effects can reduce the number of defects at grain boundaries of poly-Si in active regions for high performances. (c) 2005 The Electrochemical Society. All rights reserved.
Effects of channel width on electrical characteristics of polysilicon TFTs with multiple nanowire channels
(2005-10-01)
Wu, YC
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Chang, TC
;
Liu, PT
;
Chen, CS
;
Tu, CH
This brief studies the electrical characteristics of a series of polysilicon thin-film transistors (poly-Si TFTs) with different numbers of multiple channels of various widths, with lightly doped drain (LDD) structures. The nanoscale TFT with ten 67-nm-wide split channels (M10) has superior and more uniform electrical characteristics than other TFTs. Additionally, experimental results reveal that the electrical performance of proposed TFTs enhances with each channel width decreasing, yielding a profile from a single-gate to tri-gate structure.
Enhanced performance of poly-Si thin film transistors using fluorine ions implantation
(2005)
Tu, CH
;
Chang, TC
;
Liu, PT
;
Zan, HW
;
Tai, YH
Fluorine (F)-implanted polycrystalline silicon thin-film transistor (poly-Si TFT) are proposed for the enhancement of device performance. A significant improvement in electrical characteristics, such as I-ON/I-OFF ratio, and field effect mobility, can be realized in the new thin-film transistor. The field effect mobility for F-implanted poly-Si TFTs is 53.82 cm(2)/V-s, and higher than 19.74 cm(2)/V-s in conventional SPC poly-Si TFTs. Furthermore, the F-implanted poly- Si TFT exhibits high immunity against hot carrier effect and improved electrical reliability. The manufacturing processes are simple and without additional thermal annealing steps, thereby compatible with the conventional TFT fabrication processes. (c) 2005 The Electrochemical Society. All rights reserved.
High performance and high reliability polysilicon thin-film transistors with multiple nano-wire channels
(2004)
Wu, YC
;
Chang, CY
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Chang, TC
;
Liu, PT
;
Chen, CS
We have investigated the lightly-doped drain (LDD) polysilicon thin-film transistors (poly-Si TFTs) with a series of multi-channel with different widths. The ten 67 nm-wide split channels TFT has best gate control due to its tri-gate structure, and has lowest poly-Si grain boundary defects, which were passivated by NH3 plasma effectively due to its split nano-wires structure. The proposed TFT exhibits high performance electrical characteristics, such as a high ON/OFF current ratio (>10(9)), a steep subthreshold slope (SS) of 137 mV/decade, an absence of drain-induced barrier lowering (DIBL), suppressed kink-effect, and superior reliability.
High-performance metal-induced lateral-crystallization polysilicon thin-film transistors with multiple nanowire channels and multiple gates
(2006-05-01)
Wu, YC
;
Chang, TC
;
Liu, PT
;
Chou, CW
;
Wu, YC
In this study, pattern-dependent nickel (Ni) metal-induced lateral-crystallization (Ni-MILC) polysilicon thin-film transistors (poly-Si TFTs) with ten nanowire channels and multigate structure were fabricated and characterized. Experimental results reveal that applying ten nanowire channels improves the performance of an Ni-MILC poly-Si TFT, which thus has a higher ON current, a lower leakage current, and a lower threshold voltage (V-th) than single-channel TFTs. Furthermore, the experimental results reveal that combining the multigate structure and ten nanowire channels further enhances the entire performance of Ni-MILC TFTs, which thus have a low leakage current, a high ON/OFF ratio, a low Vth, a steep subthreshold swing, and kink-free output characteristics. The multigate structure with ten-nanowire-channel Ni-MILC TFTs has a few poly-Si grain boundary defects, a low lateral electrical field, and a gate-channel shortening effect, all of which are associated with such high-performance characteristics.
High-performance polycrystalline silicon thin-film transistor with multiple nanowire channels and lightly doped drain structure
(2004-05-10)
Wu, YC
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Chang, TC
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Chang, CY
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Chen, CS
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Tu, CH
This investigation examines polycrystalline silicon thin-film transistors (TFTs) with multiple nanowire channels and a lightly doped drain (LDD). A device with an LDD structure exhibits low leakage current because the lateral electrical field is reduced in the drain offset region. Additionally, multiple nanowire channels can generate fewer defects in the polysilicon grain boundary and have more efficient NH3 plasma passivation than single-channel TFTs, further reducing leakage current. They exhibit superior electrical characteristics to those of single-channel TFTs, such as a higher ON/OFF current ratio (>10(8)), a better subthreshold slope of 110 mV/decade, an absence of drain-induced barrier lowering, and suppressed kink-effect. Devices with the proposed TFTs are highly promising for use in active-matrix liquid-crystal display technologies. (C) 2004 American Institute of Physics.
Improvement of electrical characteristics for fluorine-ion-implanted poly-Si TFTs using ELC
(2006-04-01)
Tu, CH
;
Chang, TC
;
Liu, PT
;
Yang, CY
;
Liu, HC
The fluorine ion implantation applied to the polycrystalline silicon thin-film transistors (poly-Si TFTs) is investigated in this letter. Experimental results have shown that fluorine ion implantation effectively minimized the trap state density, leading to superior electrical characteristics such as high field-effect mobility, low threshold voltage, and high ON/OFF current ratio. Furthermore, the fluorine ions tended to segregate at the interface between the gate oxide and poly-Si layers during the excimer laser annealing, even without the extra deposition of pad oxide on the poly-Si film. The presence of fluorine obviously enhanced electrical reliability of poly-Si TFTs.
Improvement of reliability for polycrystalline thin-film transistors using self-aligned fluorinated silica glass spacers
(2005)
Tu, CH
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Chang, TC
;
Liu, PT
;
Zan, HW
;
Tai, YH
Polycrystalline silicon thin-film transistors (poly-Si TFTs) with self-aligned fluorine-doped SiO2 (FSG) spacer were investigated in this study. The presence of FSG spacers can effectively reduce the lateral electrical field near the drain side of a poly-Si TFT device, and strongly passivate Si dangling bonds at the grain boundaries. The significant enhancement in electrical performance suppresses serious kink effect and improves electrical reliability of poly-Si TFTs effectively. In addition, the proposed poly-TFT structure is uncomplicated and compatible with existing TFT manufacturing processes. (c) 2005 The Electrochemical Society.
Mobility enhancement of polycrystalline-Si thin-film transistors using nanowire channels by pattern-dependent metal-induced lateral crystallization
(2005-10-03)
Wu, YC
;
Chang, TC
;
Liu, PT
;
Wu, YC
;
Chou, CW
This work presents a method for enhancing the mobility of polycrystalline-Si (poly-Si) thin-film transistors (TFTs) by pattern-dependent metal-induced-lateral-crystallization (PDMILC) using nanowire channels. Experimental results indicate that the field-effect mobility of PDMILC TFT was enhanced as the channel width decreased, because the lateral length of the poly-Si grains increased. The PDMILC poly-Si TFT with ten nanowire channels (M10) had the greatest field-effect mobility, 109.34 cm(2)/V s and the lowest subthreshold swing, 0.23 V/dec, at a gate length of 2 mu m. The field-effect mobility also increased as the gate length in the M10 PDMILC poly-Si TFT device declined, because the number of poly-Si grain-boundary defects was reduced. (C) 2005 American Institute of Physics.
Numerical solution for the second-order wave interaction with porous structures
(1999-02-15)
Hsu, HH
;
Wu, YC
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土木工程學系
;
Department of Civil Engineering
This study mathematically formulates the fluid field of a water-wave interaction with a porous structure as a two-dimensional, non-linear boundary value problem (bvp) in terms of a generalized velocity potential. The non-linear bvp is reformulated into an infinite set of linear bvps of ascending order by Stokes perturbation technique, with wave steepness as the perturbation parameter. Only the first- and second-order linear bvps are retained in this study. Each linear bvp is transformed into a boundary integral equation. In addition, the boundary element method (BEM) with linear elements is developed and applied to solve the first- and second-order integral equations. The first- and second-order wave profiles, reflection and transmission coefficients, and the amplitude ratio of the second-order components are computed as well. The numerical results correlate well with previous analytical and experimental results. Numerical results demonstrate that the second-order component can be neglected for a deep water-wave and may become significant for an intermediate depth wave. Copyright (C) 1999 John Wiley & Sons, Ltd.
Postnatal expression of growth/differentiation factor-8 (GDF-8) gene in European and Asian pigs
(2002-09-01)
Lin, CS
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Wu, YC
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Sun, YL
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Huang, MC
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生物科技學系
Myostatin (growth differentiation factor (GDF)-8), is one member of the transforming growth factor beta superfamily. Investigations of GDF-8 null mice and double-muscled cattle revealed that GDF-8 has a profound influence upon skeletal muscle growth. Therefore, the GDF-8 effect upon the productive performance of pigs is worth exploring. In the present study, the nucleotide sequences and expression levels of GDF-8 genes in European pigs (Landrace and Duroc) and Asian pigs (Taoyuan and Small-ear) were evaluated. Based upon their genetic background these breeds possess significantly distinct growth rate and muscle production-phenotypes. Our sequence data showed that the nucleotide sequences of European and Asian pigs were 100% similar. Postnatal expression of GDF-8 gene in skeletal muscles, from birth to 12 mo of age, among different breeds was measured. GDF-8 expression levels in the longissimus muscle of neonatal European breed littermates were the highest, however it declined significantly (p<0.05) at 1 and 3 mo, and then increased gradually at 6 to 12 mo. The Asian breeds, however, GDF-8 expression level increased markedly at 3 mo and maintained a constant level thereafter. The results indicate that rather than polymorphism within the GDF-8 functional sequence between European and Asia breeds, it was relative to the gene regulation in postnatal muscle growth.
Reduction of etching plasma damage on low dielectric constant fluorinated amorphous carbon films by multiple H-2 plasma treatment
(2002-07-01)
Shieh, JM
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Tsai, KC
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Dai, BT
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Wu, YC
;
Wu, YH
Two-step hydrogen plasma treatment on low dielectric constant (low-k) fluorinated amorphous carbon films (a-C:F) was conducted to improve their thermal stability and reduce the damage caused by the patterning processes. First, hydrogen plasma treatment repairs imperfect bonds of as-deposited a-C:F films, stabilizing their chemical structures and increasing their resistance against elevated thermal stresses. After this passivation process, an additional hydrogen plasma treatment was applied to a-C:F films that had been etched using a mixture of N-2+O-2+CHF3, enabling sub-130 nm damascene trenches to be patterned and repairing the chemical structures destroyed by the etching plasma. (C) 2002 American Vacuum Society.
Reduction of leakage current in metal-induced lateral crystallization polysilicon TFTs with dual-gate and multiple nanowire channels
(2005-09-01)
Wu, YC
;
Chang, TC
;
Liu, PT
;
Chou, CW
;
Wu, YC
This letter addresses the leakage current in nickel (Ni) metal-induced lateral crystallization (Ni-MILC) polysilicon thin-film transistors (poly-Si TFTs) with multiple nanowire channels and dual-gate. Experimental results reveal that applying multiple nanowire channels improves the Ni-MILC poly-Si TFT performance. However, the leakage current of both single-gate with single-channel and multiple nanowire channels remains high (> 10(-8) A), because of the field emission of carriers through the poly-Si grain traps and the defects caused by Ni contamination. Applying the dual-gate structure can suppress the electrical filed in the drain depletion region, significantly reducing the leakage current of the Ni-MILC poly-Si TFT, increasing the ON/OFF ratio.
Room temperature two-terminal characteristics in silicon nanowires
(2003-02-01)
Hu, SF
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Wong, WZ
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Liu, SS
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Wu, YC
;
Sung, CL
Quantum effects in silicon nanowires due to one-dimensional carrier confinement were observed at room temperature. Electrical transport properties were measured, on narrow thin-silicon-on-insulator wires that were defined by e-beam lithography and further narrowed and thinned down by oxidation to a final thickness of around 3 nm, and a width of 29 nm. The room temperature current-voltage characteristics of the resulting silicon nanowires are shown to exhibit a zero current state may be due to the occurrence of Coulomb blockade. (C) 2003 Elsevier Science Ltd. All rights reserved
Scattering of water wave by a submerged horizontal plate and a submerged permeable breakwater
(1999-04-01)
Hsu, HH
;
Wu, YC
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土木工程學系
;
Department of Civil Engineering
Based on a two-dimensional linear water wave theory, this study develops the boundary element method (BEM) to examine normally incident wave scattering by a fixed, submerged, horizontal, impermeable plate and a submerged permeable breakwater in water of finite depth. Numerical results for the transmission coefficients are also presented. In addition, the numerical technique's accuracy is demonstrated by comparing the numerical results with previously published numerical and experimental ones. According to that comparison, the transmission coefficient relies not only on the submergence of the horizontal impermeable plate and the height of the permeable breakwater, but also on the distance between horizontal plate and permeable breakwater. Results presented herein confirm that the transmission coefficient is minimum for the distance approximately equal to four times the water depth. (C) 1998 Elsevier Science Ltd. All rights reserved.
Study on SONOS nonvolatile memory technology using high-density plasma CVD silicon nitride
(2004)
Chang, TC
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Yan, ST
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Liu, PT
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Chen, CW
;
Wu, YC
With the replacement of silicon nitride in an oxide/nitride/oxide (ONO) gate-stacked structure, trap-rich high-density plasma chemical vapor deposited (HDPCVD) SiNx shows a more significant threshold-voltage shift (memory window) than that of conventional low pressure (LP)CVD Si3N4. Also, low-temperature (2000degreesC) deposited HDPCVD silicon nitride shows a good retention characteristic, the same as high-temperature (780degreesC) LPCVD Si3N4. With the optimization of thickness in the gate-stacked ONO structure, low-voltage and reliable operation, lower than 5 V, is realizable. (C) 2004 The Electrochemical Society.