Browsing by Author "Wu, YewChung Sermon"

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Anomalous SAXS for the morphology and metal content of a metallothionein in a metal-atom replacement
(2008-01-01)
Jeng, U-Ser
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Li, Meiyi
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Hsu, I-Jui
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Huang, Yu-Shan
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Wu, YewChung Sermon
Crystal Quality and Light Output Power of GaN-Based LEDs Grown on Concave Patterned Sapphire Substrate
(2015-04-01)
Wu, YewChung Sermon
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Isabel, A. Panimaya Selvi
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Zheng, Jian-Hsuan
;
Lin, Bo-Wen
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Li, Jhen-Hong
The crystal quality and light output power of GaN-based light-emitting diodes (LEDs) grown on concave patterned sapphire substrate (CPSS) were investigated. It was found that the crystal quality of GaN-based LEDs grown on CPSS improved with the decrease of the pattern space (percentage of c-plane). However, when the pattern space decreased to 0.41 mu m (S0.41-GaN), the GaN crystallinity dropped. On the other hand, the light output power of GaN-based LEDs was increased with the decrease of the pattern space due to the change of the light extraction efficiency.
Crystal Quality and Light Output Power of GaN-Based LEDs Grown on Nanoporous Patterned Sapphire Substrate
(2014)
Chen, Chien-Chih
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Yap, Chun-Yan
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Hsu, Wen-Yang
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Kuo, Cheng-Ta
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Tsai, Tzong-Liang
The crystal quality and light output power of GaN-based LEDs grown on nanoporous patterned sapphire substrate (NPSS) were investigated. NPSS was prepared using an anodized aluminum oxide (AAO) layer. It was found that the crystal quality of GaN-based LEDs grown on NPSS was better than that on micron-sized patterned sapphire substrate (MPSS) and conventional sapphire substrate. However, the light output power of GaN-based LEDs grown on NPSS was smaller than that on MPSS because the light extraction efficiency (LEE) of MPSS was much larger than that of NPSS. (C) 2014 The Electrochemical Society. All rights reserved.
Effect of CF(4) Plasma on Properties and Reliability of Metal-Induced Lateral Crystallization Silicon Transistors
(2010-01-01)
Chang, Chih-Pang
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Wu, YewChung Sermon
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材料科學與工程學系
;
Department of Materials Science and Engineering
In this study, a CF(4) plasma etching treatment was applied to metal-induced lateral crystallization (MILC) polycrystalline silicon thin film transistors (poly-Si TFTs). It was found that the electrical properties and reliability of the MILC poly-Si TFTs were improved by the treatment. The minimum off-state currents were also reduced. This is because this etching method involves not only passivating the trap states but also etching away the Ni-related defects on the top surface of MILC poly-Si.
Effect of CF4 Plasma on Properties and Reliability of Metal-Induced Lateral Crystallization Silicon Transistors
(2010-01-01)
Chang, Chih-Pang
;
Wu, YewChung Sermon
;
材料科學與工程學系
;
Department of Materials Science and Engineering
In this study, a CF4 plasma etching treatment was applied to metal-induced lateral crystallization (MILC) polycrystalline silicon thin film transistors (poly-Si TFTs). It was found that the electrical properties and reliability of the MILC poly-Si TFTs were improved by the treatment. The minimum off-state currents were also reduced. This is because this etching method involves not only passivating the trap states but also etching away the Ni-related defects on the top surface of MILC poly-Si.
Effect of Ni residues on the performance and the uniformity of nickel-induced lateral crystallization polycrystalline silicon nanowire thin-film transistors
(2010-11-01)
Wang, Bau-Ming
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Yang, Tzu-Ming
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Wu, YewChung Sermon
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Su, Chun-Jung
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Lin, Horng-Chih
High performance nickel-induced lateral crystallization (NILC) polycrystalline silicon (poly-Si) nanowire (NW) thin-film transistors (TFTs) were fabricated. The phosphorous-doped amorphous silicon (alpha-Si)/chem-SiO(2) films were employed as Ni-gettering layers to investigate effect of Ni residues on the performance and the uniformity of NILC poly-Si NW TFTs. It was found that the performance and the uniformity of NW TFTs were greatly improved after Ni-gettering process. (C) 2010 Elsevier B.V. All rights reserved.
Effect of Ni residues on the performance and the uniformity of nickel-induced lateral crystallization polycrystalline silicon nanowire thin-film transistors
(2010-11-01)
Wang, Bau-Ming
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Yang, Tzu-Ming
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Wu, YewChung Sermon
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Su, Chun-Jung
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Lin, Horng-Chih
High performance nickel-induced lateral crystallization (NILC) polycrystalline silicon (poly-Si) nanowire (NW) thin-film transistors (TFTs) were fabricated. The phosphorous-doped amorphous silicon (alpha-Si)/chem-SiO(2) films were employed as Ni-gettering layers to investigate effect of Ni residues on the performance and the uniformity of NILC poly-Si NW TFTs. It was found that the performance and the uniformity of NW TFTs were greatly improved after Ni-gettering process. (C) 2010 Elsevier B.V. All rights reserved.
Effect of Nickel Concentration on Bias Reliability and Thermal Stability of Thin-Film Transistors Fabricated by Ni-Metal-Induced Crystallization
(2012-01-01)
Lai, Ming-Hui
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Wu, YewChung Sermon
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Huang, Jung-Jie
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材料科學與工程學系
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Department of Materials Science and Engineering
Ni-metal-induced crystallization (MIC) of amorphous Si (alpha-Si) has been employed to fabricate low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). Although the high leakage current is a major issue in the performance of conventional MIC-TFTs since Ni contamination induces deep-level state traps, it can be greatly improved by using well-known technologies to reduce Ni contamination. However, for active-matrix organic light-emitting diode (AMOLED) display applications, the bias reliability and thermal stability are major concerns especially when devices are operated under a hot carrier condition and in a high-temperature environment. It will be interesting to determine how the bias reliability and thermal stability are affected by the reduction of Ni concentration. In the study, the effect of Ni concentration on bias reliability and thermal stability was investigated. We found that a device exhibited high immunity against hot-carrier stress and elevated temperatures. These findings demonstrated that reducing the Ni concentration in MIC films was also beneficial for bias reliability and thermal stability. (C) 2012 The Japan Society of Applied Physics
Effect of Nickel Concentration on Bias Reliability and Thermal Stability of Thin-Film Transistors Fabricated by Ni-Metal-Induced Crystallization
(2012-01-01)
Lai, Ming-Hui
;
Wu, YewChung Sermon
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Huang, Jung-Jie
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Ni-metal-induced crystallization (MIC) of amorphous Si (alpha-Si) has been employed to fabricate low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). Although the high leakage current is a major issue in the performance of conventional MIC-TFTs since Ni contamination induces deep-level state traps, it can be greatly improved by using well-known technologies to reduce Ni contamination. However, for active-matrix organic light-emitting diode (AMOLED) display applications, the bias reliability and thermal stability are major concerns especially when devices are operated under a hot carrier condition and in a high-temperature environment. It will be interesting to determine how the bias reliability and thermal stability are affected by the reduction of Ni concentration. In the study, the effect of Ni concentration on bias reliability and thermal stability was investigated. We found that a device exhibited high immunity against hot-carrier stress and elevated temperatures. These findings demonstrated that reducing the Ni concentration in MIC films was also beneficial for bias reliability and thermal stability. (C) 2012 The Japan Society of Applied Physics
Effect of nickel concentration on source/drain series resistance and channel resistance of Ni-metal-induced crystallization thin-film transistors
(2013-10-01)
Lai, Ming-Hui
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Wu, YewChung Sermon
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Huang, Jung-Jie
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材料科學與工程學系
;
Department of Materials Science and Engineering
The Ni-metal-induced crystallization (MIC) of amorphous Si (a-Si) has been employed to fabricate low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). Most studies have focused only on reducing Ni contamination because Ni residues cause high leakage current in MIC-TFTs. Also of concern is the source/drain (S/D) series resistance, which degrades the device performance (driving ability) that might vary with the Ni concentration in MIC-TFTs. Improving the driving ability of MIC-TFTs requires a detailed understanding of how Ni residues affect S/D series resistance. This study investigates how Ni concentration affects S/D series resistance by using the transmission line method. The results of this study provide further insight into how Ni concentration and resistance are related. The results show that the S/D series resistance and channel resistance decreased with a reduction in Ni concentration in MIC poly-Si because of better crystalline quality and lower degradation of the donor concentration. This phenomenon was caused by the Ni concentration forming less NiSi2 nucleation sites to generate a large grain size; Ni atoms serve as acceptor-like dopants in silicon, which counteract with the effects of n-type doping, subsequently reducing the donor concentration in the S/D region. (C) 2013 Elsevier B. V. All rights reserved.
Effect of Sputtered AlN Location on the Growth Mechanism of GaN
(2017-01-01)
Wu, Pei-Yu
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Li, Jhen-Hong
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Hsu, Lung-Hsing
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Huang, Chia-Yen
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Cheng, Yuh-Jen
Patterned sapphire substrates (PSSs) have been used to enhance the performance of GaN-based light-emitting diodes (LEDs). This performance can be further improved by using an ex situ sputtered AlN nucleation layer. This improvement has been attributed to the reduction of the GaN formation on the sidewall of the cone shape pattern. In this study, four kinds of PSS samples were fabricated to investigate the effect of sputtered AlN location on the growth mechanism of GaN in detail. (c) 2017 The Electrochemical Society. All rights reserved.
Effect of the silver mirror location on the luminance intensity of double-roughened GaN light-emitting diodes
(2007)
Wu, YewChung Sermon
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Liao, Cheng
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Peng, Wei Chih
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材料科學與工程學系
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Department of Materials Science and Engineering
Three kinds of GaN light-emitting diodes (LEDs) were used to investigate the effect of the silver (Ag) mirror location on the performance of LEDs. Samples designated as "PR-LED" were LEDs with roughened p-GaN surface. "DRM-LED" and "DRSM-LED" were LEDs with double-roughened (p-GaN and undoped-GaN) surfaces and a Ag mirror system either at the undopedGaN/sapphire interface or on the back side of sapphire substrate. It was found that the light intensity of DRM-LED was 235.8 mcd, which was 3.05 times higher than that of the PR-LED, and 1.45 times higher than that of the DRSM-LED. (c) 2007 The Electrochemical Society.
Effects of Laser Sources on Damage Mechanisms and Reverse-Bias Leakages of Laser Lift-Off GaN-Based LEDs
(2009)
Cheng, Ji-Hao
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Wu, YewChung Sermon
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Peng, Wei Chih
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Ouyang, Hao
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材料科學與工程學系
The frequency-tripled neodymium-doped yttrium aluminum garnet laser (355 nm) and the KrF pulsed excimer laser (248 nm) were employed to separate GaN thin films from sapphire substrates and to transfer the films to bond with other substrates. The different laser lift-off processes would generate the dislocation density on different regions. In this study, the effects of these two laser sources on structural damage mechanisms and reverse-bias leakages of InGaN-GaN light-emitting diodes (LEDs) were studied.
Enhanced Extraction and Efficiency of Blue Light-Emitting Diodes Prepared Using Two-Step-Etched Patterned Sapphire Substrates
(2009)
Lin, Ray-Ming
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Lu, Yuan-Chieh
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Yu, Sheng-Fu
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Wu, YewChung Sermon
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Chiang, Chung-Hao
Using a hot acid wet etching method, we have fabricated two types of patterned sapphire substrates: A pyramidal patterned sapphire substrate (PPSS) and a flat-top patterned sapphire substrate (FTPSS). After placing these samples into an atmospheric pressure metallorganic chemical vapor deposition system, we deposited standard InGaN light-emitting diode (LED) structures onto their surfaces. The crystal quality of these two surfaces was enhanced, as evidenced using X-ray diffraction (the full width at half-maximum decreased from 406.8 arcsec for the conventional sapphire to 356.4 and 349.2 arcsec for the PPSS and FTPSS samples, respectively). The output power of InGaN-based blue LEDs incorporating the PPSS and FTPSS improved to 17.9 and 18.7%, respectively, at 20 mA. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3231502] All rights reserved.
Enhanced performance and reliability of NILC-TFTs using FSG buffer layer
(2012-02-15)
Chen, Chien-Chih
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Wu, YewChung Sermon
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Chang, Chih-Pang
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材料科學與工程學系
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Department of Materials Science and Engineering
A new manufacturing method for Ni-metal-induced lateral crystallization thin film transistors (NILC-TFTs) using fluorine-silicate-glass (FSG) was proposed. In FSG-TFTs, fluorine ion was implanted into the buffer oxide layer to form FSG before NILC processes. It was found FSG-TFTs exhibit high field-effect mobility, low threshold voltage, low subthreshold slope, high ON/OFF current ratio, low trap state density, low interface trap state density, and good reliability compared with typical NILC-TFTs. (c) 2011 Elsevier B.V. All rights reserved.
Enhanced Performance of LEDs Using Periodic Tent-Like Post Patterns on A-plane Sapphire Substrates
(2011-12-01)
Lin, Bo-Wen
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Chang, Chung-Cheng
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Hsieh, Cheng-Yu
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Wang, Bau-Ming
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Wu, YewChung Sermon
Periodic tent-like post patterns on a-plane sapphire substrates were fabricated using a two-step etching process. They were denoted as a-plane dot pattern sapphire substrate (ADPSS). Compared with the GaN-based light-emitting diode (LED) grown on a-plane sapphire without any pattern (AFlat), the ADPSS-LED has higher output power, light extraction efficiency (LEE), and external quantum efficiency (EQE), and better crystal quality. The output power of ADPSS-LED was 9.6 mW, which was 68.4% larger than the AFlat-LED. In addition, the blue shift of ADPSS-LED was found to be less than that of AFlat-LED.
Evolution of Bottom c-Plane on Wet-Etched Patterned Sapphire Substrate
(2013)
Chen, Chien-Chih
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Hsiao, Feng Ching
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Lin, Bo-Wen
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Hsu, Wen-Ching
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Wu, YewChung Sermon
Wet-etched pattern sapphire substrate (PSS) has been employed to improve the epitaxy of GaN-based LEDs. It was found that the crystal quality and performance of LEDs improved with decrease in c-plane areas of PSS. However, further decrease in bottom c-plane areas makes epitaxy of GaN film very difficult. In this research, the evolution of bottom c-plane was investigated through a systematic study. It was found that epitaxy difficulty might be due to the appearance of 6C facets {4 (1) over bar(3) over bar 18} and the disappearance of bottom c-plane. (C) 2013 The Electrochemical Society.
Gettering of Ni from Ni-metal induced lateral crystallization polycrystalline silicon films using a gettering substrate
(2006-09-01)
Hou, Chih-Yuan
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Lin, Chi-Ching
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Wu, YewChung Sermon
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材料科學與工程學系
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Department of Materials Science and Engineering
Ni-metal-induced lateral crystallization (NILC) of amorphous silicon (alpha-Si) has been employed to fabricate high-performance low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). However, the current crystallization technology often leads to trapped Ni and NiSi2 precipitates, thus degrading the device performance. We proposed using a-Si-coated wafers as Ni-gettering substrates. By bonding the gettering substrate and NILC poly-Si film together, the Ni-metal impurity within the NILC poly-Si film was greatly reduced.
Gettering of Ni from Nickel-Induced Lateral Crystallization Silicon Using Amorphous Silicon and Chemical Oxide
(2009)
Wang, Bau-Ming
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Wu, YewChung Sermon
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材料科學與工程學系
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Department of Materials Science and Engineering
Nickel contamination inside nickel-metal-induced lateral crystallization (NILC) polycrystalline silicon poses a problem in the fabrication of high-performance thin-film transistors. In this study, amorphous Si (alpha-Si) and chemical oxide (chem-SiO(2)) films were employed to reduce the impurity of Ni-metal within the NILC film. The top 100 nm thick alpha-Si layer served as a gettering layer, while the middle 5 nm thick chem-SiO(2) layer served as an etching stop layer. It was found that nickel contamination was greatly reduced after annealing at 550 degrees C for only 12 h.
Gettering of nickel within the Ni-metal induced lateral crystallization polycrystalline silicon film through the contact holes
(2007-12-01)
Hu, Chen-Ming
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Wu, YewChung Sermon
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材料科學與工程學系
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Department of Materials Science and Engineering
Ni-metal-induced lateral crystallization (NILC) of amorphous Si (alpha-Si) has been used to fabricate high-performance low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs). The current crystallization technology, however, often leads to trap Ni and NiSi2 precipitates, which degrade the device performance. In this study, alpha-Si film was coated on the top of contact holes as Ni-gettering layer. It was found the Ni-metal impurity within the NILC poly-Si film was reduced without addition mask.