Browsing by Author "Chang, C. T."

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Characteristics of Zinc Oxide Thin Film Transistors Fabricated by Location-Controlled Hydrothermal Method
(2010)
Yang, P. Y.
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Wang, J. L.
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Tsai, W. C.
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Wang, S. J.
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Chen, P. C.
In this paper, high-performance Zinc oxide (ZnO) thin-film transistors (TFTs) with bottom-gate (BG) structure and artificially location-controlled lateral grain growth have been prepared by low-temperature hydrothermal method. As the proper design of source/drain structure of ZnO/Ti/Pt thin films, the lateral grain growth can be artificially controlled in the desired location and the vertical grain boundary perpendicular to the current flow in the channel region can be reduced to single one. As compared with the conventional sputtered ZnO BG-TFTs, the proposed location-controlled hydrothermal ZnO BG-TFTs (W/L = 250 mu m/10 mu m) demonstrated the higher field-effect mobility of 6.09 cm(2)/V.s, lower threshold voltage of 3.67 V, larger on/off current ratio above 10(6), and superior current drivability, which can be attributed to the high-quality ZnO thin films with the reduced vertical grain boundaries in the channel region.
Growth and Field Emission Characteristics of Pillar-like Carbon Nanotubes Using Co-Ti/Al Co-deposited Catalysts at Low Temperature
(2010)
Chang, C. T.
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Lee, C. Y.
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Lin, K. C.
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Lai, R. L.
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Tsai, Wan-Lin
In this essay, the pillar-like CNT field emission arrays synthesis with co-deposited catalysts at low temperature (550 degrees C) was proposed. Pillar-like CNT has been successfully synthesized by thermal CVD system. The current density of this proposed pillar like CNTs was as high as 1272 mu A/cm(2) at 6 V/mu m and the turn-on field was 3.6 V/mu m. Additionally, the reliability was more stable as lower than 7% degradation of initial current density.
Improved Field Emission Characteristics with different Electrode Materials by forming process in a Quasi-planar Thin Film Field Emission Diode
(2010-01-01)
Chang, C. T.
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Hsu, Y. Y.
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Lin, K. C.
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Tsai, Wan-Lin
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Chien, Yun-Shan
The essay was reported the different electrode materials in a quasi-planar thin film field emission diode by different forming process. The forming process causes an increased surface roughness of emitters or reduced the work function of the emitter and results in a higher field enhancement factor, which shows better field emission characteristics. The turn on voltage could from 15 V to 8 V and 6.5V with Co and Pd electrode at the emission current of 100 nA for samples.
Improving TDDB Reliability in Cu Damascene by modulating ESL Structure
(2012)
Chang, C. T.
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Chang, H. L.
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材料科學與工程學系
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Department of Materials Science and Engineering
Low k time-dependent dielectric breakdown (TDDB) is increasing becoming a major issue at 28 nm and beyond. Although TDDB models, such as E model, the root E model and the 1/E model, have been extensively explored, determining the BEOL processing direction for TDDB warrants further study. This study attempts to determine whether the thickness of the etching stop layer film influences the electron conduction mechanism. Cu damascene structures were designed following three approaches with ESL in various thicknesses. They were Co/ESL=0A-550A (LK: SiCO k= 3.1), Cu/ESL=0A-275A (ELK: SiCO k=2.5) and Co/ESL=0A-275A (ELK: SiCO k=2.5). Analytical results demonstrated superior breakdown fields of 8.5 MV/cm, 7.5 MV/cm and 7.5 MV/cm for Co/ESL=0A (SiCO k=3.1), Cu/ESL =0A (SiCO k=2.5) and Co/ESL =0A (SiCO k=2.5), respectively. TDDB results further reveal that the ESL=0A structure is essential to a long TDDB lifetime, because electrons are conducted through the ESL bulk film. The mechanism of TDDB improvement is considered to be the absence of ESL, the modified metal/LK electrical potential and the negligibility of interfacial LK/LK surface defects.
Nanostructured Material Formation for Beyond Si Devices
(2015)
Chang, H. L.
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Chang, C. T.
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Kuo, C. T.
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材料科學與工程學系
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Department of Materials Science and Engineering
Beyond Si CMOS technology is the current challenging for next generation transistor. As demand for nano-scaled devices increase, the ability to manipulate the building blocks of electronic is essential. Catalytic-assisted CNTs are integrated into trenches, holes, parallel plates under CH4/H-2 gases by microwave plasma chemical vapor deposition or electron cyclotron resonance deposition. The trench and parallel plates are used to fabricate for gate electrodes, while the holes are used to make interconnections. Results indicate the orientation of grown CNTs is dominated by pattern geometry. The field emission results show that the CNTs exhibit robust electronic properties with emission densities of over 1mA/cm(2) at 3.97 and 6.30 V/mu m indicating the high electron emission efficiency as the CNT field effect transistor application. The growth models of Fe, Ni and CoSi2 and application for nanoclectronics are purposed.
Study of Conduction Modes of Time to Dielectric Breakdown Reliability in Cu Damascene Structures
(2013)
Chang, H. L.
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Chang, C. T.
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Kuo, C. T.
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材料科學與工程學系
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Department of Materials Science and Engineering
Low k time-dependent dielectric breakdown is increasingly becoming a major issue at the 45 nm technology node and beyond. Although TDDB models, such as the root E model, the v E model and the 1/E model, have been extensively explored, determining the back end of line processing direction for TDDB warrants further study. This study attempts to determine whether the thickness of the etching stop layer film influences the electron conduction mechanism. Cu damascene structures were designed following three approaches with various thickness of the etching stop layer : Co/ESL = 0 A-550 A (low-k: SiCO k = 3.1), Cu/ESL = 0 A-275 A (low-k: SiCO k = 2.5) and Co/ESL = 0 A-275 A (low-k: SiCO k = 2.5). The application of capping material Co is warranted for electron emission suppression, but the oxygen attacking from subsequent low-k deposition is a concern. In addition, greater ESL thickness offers paths for electron conduction which worsens TDDB; i.e., less ESL thickness is better. Therefore, the combination of Co with SiH4 treatment addresses optimized conditions to achieve an ESL-less application for TDDB enhancement. (C) 2013 The Electrochemical Society. All rights reserved.
The influences of surface treatment and gas annealing conditions on the inversion behaviors of the atomic-layer-deposition Al(2)O(3)/n-In(0.53)Ga(0.47)As metal-oxide-semiconductor capacitor
(2010-07-26)
Trinh, H. D.
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Chang, E. Y.
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Wu, P. W.
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Wong, Y. Y.
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Chang, C. T.
The inversion behaviors of atomic-layer-deposition Al(2)O(3)/n-In(0.53)Ga(0.47)As metal-oxide-semiconductor capacitors are studied by various surface treatments and postdeposition annealing using different gases. By using the combination of wet sulfide and dry trimethyl aluminum surface treatment along with pure hydrogen annealing, a strong inversion capacitance-voltage (C-V) response is observed, indicating a remarkable reduction in interface trap state density (D(it)) at lower half-part of In(0.53)Ga(0.47)As band gap. This low D(it) was confirmed by the temperature independent C-V stretch-out and horizontal C-V curves. The x-ray photoelectron spectroscopy spectra further confirm the effectiveness of hydrogen annealing on the reduction of native oxides. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467813]
The influences of surface treatment and gas annealing conditions on the inversion behaviors of the atomic-layer-deposition Al2O3/n-In0.53Ga0.47As metal-oxide-semiconductor capacitor
(2010-07-26)
Trinh, H. D.
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Chang, E. Y.
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Wu, P. W.
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Wong, Y. Y.
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Chang, C. T.
The inversion behaviors of atomic-layer-deposition Al2O3/n-In0.53Ga0.47As metal-oxide-semiconductor capacitors are studied by various surface treatments and postdeposition annealing using different gases. By using the combination of wet sulfide and dry trimethyl aluminum surface treatment along with pure hydrogen annealing, a strong inversion capacitance-voltage (C-V) response is observed, indicating a remarkable reduction in interface trap state density (D-it) at lower half-part of In0.53Ga0.47As band gap. This low D-it was confirmed by the temperature independent C-V stretch-out and horizontal C-V curves. The x-ray photoelectron spectroscopy spectra further confirm the effectiveness of hydrogen annealing on the reduction of native oxides. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467813]
UV photodetectors with lateral self-assembled ZnO nanowires grown at low temperature
(2009)
Yang, P. Y.
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Lee, I. C.
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Chang, C. T.
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Lin, K. C.
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Wang, J. L.
In this paper, a self-assembled lateral growth of ZnO nanowire (NW) photodetector has been successfully synthesized by an aqueous solution method at low temperature (85 degrees C). The growth of ZnO NWs on a silicon substrate with a ZnO seeding layer exhibits single-phase wurtzite ZnO crystal structure, and grows along the c-axis direction. Furthermore, we have demonstrated the current-voltage characteristics and photoresponse of the ZnO NWs with and without UV (325 nm) illumination. Therefore, this low-temperature and simple fabrication process is a viable processing technique to selectively grow lateral ZnO NWs on a flat substrate of any material, with potential applications in flexible NW devices.