Browsing by Author "Zhang, Yu-Xin"

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Effects of P-Type SnOx Thin-Film Transistors with N-2 and O-2 Ambient Furnace Annealing
(2020-07-01)
Zhang, Yu-Xin
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Wu, Chien-Hung
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Chang, Kow-Ming
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Chen, Yi-Ming
;
Xu, Ni
Recently oxide-based thin-film transistors (TFTs) are investigated for emerging applications of the next generation display devices and other electronic circuits (Fortunato, E., et al., 2012. Oxide semiconductor thin-film transistors: A review of recent advances. Advanced Materials, 24, pp.2945-2986). Despite of the great success in n-type oxide semiconductors with high transparency and high field-effect mobility, high performance p-type oxide TFTs are so highly desired that complementary circuits can be realized with low power and high performance (Ou, W.C., et al., 2008. Anomalous p-channel amorphous oxide transistors based on tin oxide and their complementary circuits. Applied Physics Letters, 92, p.122113). There are some oxides such as SnO, CuO, Cu2O and NiO are regarded as promising p-type semiconductor materials. In this investigation, tin oxide SnOx is fabricated to be active layer for TFTs device, and furnace annealing with several combinations of nitrogen and oxygen ambient is compared to enhance the electrical characteristics of p-type SnOx TFTs (Park, K.S., et al., 2009. High performance solution-processed and lithographically patterned zinc-tin oxide thin-film transistors with good operational stability. Electrochemical and Solid-State Lett., 12, pp.H256-H258). The results show that with N-2 + O-2 ambient, 30 minutes furnace annealing, the p-type SnOx TFTs device shows better performance with mobility (mu(FE)) 0.883 cm(2)/V.S, threshold voltage (V-T) -4.63 V, subthreshold swing (SS) 1.15 V/decade, and I-on/I-off ratio 1.01 x 10(3).
Investigation of Electrical Characteristics on AP-PECVD Fabricated Amorphous IGZO TFTs with Hydrogen Plasma Treatment
(2019-04-01)
Wu, Chien-Hung
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Chang, Kow-Ming
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Chen, Yi-Ming
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Zhang, Yu-Xin
;
Tan, Yu-Hsuan
TFT panel production process can be divided into three kinds of technology. There have amorphous silicon (a-Si), low-temperature polysilicon (LTPS) and amorphous IGZO (a-IGZO) oxide. Traditional amorphous silicon (a-Si) silicon has a lot of advantages such as good productivity, short process and low-cost. It also has a lot of shortcomings on these applications on TFTs such as photosensitivity, light degradation, and opacity, etc. The dispute of the material based on a-Si: H as an active layer in TFT is low field effect mobility (similar to 1 cm(2)/V.S) (M. Shur and M. Hack, J. Appl. Phys. 55, 3831 (1984)), photo sensitivity (low band gap about 1.7 V) and high deposition temperature (similar to 400 degrees C) (M. Shur, et al., J. Appl. Phys. 66, 3371 (1989); K. khakzar and E. H. Lueder, IEEE Trans. Electron Devices 39, 1438 (1992)). Amorphous In-Ga-Zn-O (IGZO) had attracted attention that compared with the conventional a-Si: H, in the past three years, a-IGZO thin film transistors is more popular which compared with the other oxide semiconductors, because of its larger I-on/I-off ratio (> 10(6)), smaller subthreshold swing (SS), better field-effect mobility and better stability against electrical stress. Hydrogen plasma treatment is applied in improving a-IGZO TFTs active layer, which is fabricated by atmospheric pressure-plasma enhanced chemical vapor deposition (AP-PECVD), the electrical characteristics of a-IGZO TFTs is investigated.
Investigation of Electrical Characteristics on LaAlO3/ZrO2/IGZO TFTs with Microwave Annealing
(2019-04-01)
Wu, Chien-Hung
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Chang, Kow-Ming
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Chen, Yi-Ming
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Zhang, Yu-Xin
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Cheng, Chia-Yao
Conventional thin film transistor suffered from high threshold voltage, poor subthreshold swing, and high operation voltage. These shortcomings make the traditional thin film transistor does not meet the needs with the high-performance, high-resolution, low temperature and energy conservation nowadays. Due to the good selectivity of energy transformation and rapid heating rate, microwave annealing is promising to replace conventional furnace annealing and applied in the investigation. LaAlO3/ZrO2 is employed as gate electrode and gate dielectric layer for a-IGZO TFTs, under the premise that performance of a-IGZO TFTs without decreasing. With adjusting the power/time of microwave annealing, the effect on electrical characteristics of a-IGZO TFTs is investigated.
Investigation of Gate-Stacked In-Ga-Zn-O TFTs with Ga-Zn-O Source/Drain Electrodes by Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition
(2018-03-01)
Wu, Chien-Hung
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Chang, Kow-Ming
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Chen, Yi-Ming
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Huang, Bo-Wen
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Zhang, Yu-Xin
Atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) was employed for the fabrication of indium gallium zinc oxide thin-film transistors (IGZO TFTs) with high transparent gallium zinc oxide (GZO) source/drain electrodes. The influence of post-deposition annealing (PDA) temperature on GZO source/drain and device performance was studied. Device with a 300 degrees C annealing demonstrated excellent electrical characteristics with on/off current ratio of 2.13x10(8), saturation mobility of 10 cm(2)/V-s, and low subthreshold swing of 0.2 V/dec. The gate stacked LaAlO3/ZrO2 of AP-IGZO TFTs with highly transparent and conductive AP-GZO source/drain electrode show excellent gate control ability at a low operating voltage.
Investigation of Microwave Annealing on Resistive Random Access Memory Device with Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition Deposited IGZO Layer
(2020-07-01)
Wu, Chien-Hung
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Kuo, Song-Nian
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Chang, Kow-Ming
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Chen, Yi-Ming
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Zhang, Yu-Xin
Non-volatile memory (NVM) is essential in almost every consumer electronic products. The most prevalent NVM used nowadays is flash memory (Meena, J.S., et al., 2014. Overview of emerging nonvolatile memory technologies. Nanoscale Res. Letters, 9(1), p.526). However, some bottlenecks of flash memory have been identified, such as high operation voltage, low operation speed, and poor retention time. Resistive random access memory (RRAM) is considered to be the most promising one to become the next generation NVM device since its simple structure, fast program/erase speed, and low power consumption. In this experiment, the RRAM device is fabricated, and its IGZO (memory) layer is deposited with AP-PECVD technique which can reduce cost of the process. Microwave annealing (MWA) is used to enhance electrical characteristics of the RRAM device (Fuh, C.S., et al., 2011. Role of environmental and annealing conditions on the passivation-free In-Ga-Zn-O TFT. Thin Solid Films, 520, pp.1489-1494). Experiment results show that with appropriate MWA treatment, the IGZO RRAM device exhibits better electrical characteristics under bipolar operation, all forming/set/reset voltage for RRAM device is simultaneously lowered.
Reliability of Atmosphere Pressure-Plasma Enhanced Chemical Vapor Deposition Deposited Indium Gallium Zinc Oxide Resistive Random Access Memory Device with Microwave Annealing
(2020-07-01)
Wu, Chien-Hung
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Kuo, Song-Nian
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Chang, Kow-Ming
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Chen, Yi-Ming
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Zhang, Yu-Xin
Recently resistive random access memory (RRAM) is considered to be the most promising one to become the next generation memory since its simple Metal/Insulator/Metal (MIM) structure, lower power consumption and fabrication cost (Meena, J.S., et al., 2014. Overview of emerging nonvolatile memory technologies. Nanoscale Research Letters, 9(1), p.526). Due to some bottlenecks for current flash memory such as high operation voltage, low operation speed, poor retention time and endurance, RRAM device is regarded as an alternative solution (Fuh, C.S., et al., 2011. Role of environmental and annealing conditions on the passivation-free In-Ga-Zn-O TFT. Thin Solid Films, 520, pp.1489-1494). In this investigation, the memory layer of RRAM device is IGZO, and it is deposited with AP-PECVD technique which can operate under atmosphere, reduce cost of the process. Microwave annealing (MWA) is used to enhance the RRAM device reliability (Fuh, C.S., et al., 2011. Role of environmental and annealing conditions on the passivation-free In-Ga-Zn-O TFT. Thin Solid Films, 520, pp.1489-1494). Experiment shows that with appropriate MWA treatment, the IGZO RRAM device exhibits better electrical characteristics, reliability issues such as numbers of switching cycle and data retention time are also improved (Teng, L.F., et al., 2012. Effects of microwave annealing on electrical enhancement of amorphous oxide semiconductor thin film transistor.
Study of Atmospheric-Pressure Plasma Enhanced Chemical Vapor Deposition Fabricated Indium Gallium Zinc Oxide Thin Film Transistors with In-Situ Hydrogen Plasma Treatment
(2020-07-01)
Chen, Yi-Ming
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Wu, Chien-Hung
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Chang, Kow-Ming
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Zhang, Yu-Xin
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Xu, Ni
Amorphous InGaZnO (a-IGZO) Thin Film Transistors (TFTs) has been studied extensively for their perspective applications in next generation active-matrix displays such as liquid crystal displays and flat-panel displays, due to its better field-effect mobility (>10 cm(2)/V.S), larger I-on/I-off ratio (>10(6)), and better stability electrical. Hydrogen is known as shallow donors for n-type (channel) oxide semiconductors (Dong, J.J., et al. 2010. Effects of hydrogen plasma treatment on the electrical and optical properties of Zno films: Identification of hydrogen donors in ZnO. ACS Appl. Mater. Interfaces, 2, pp.1780-1784), and it is also effective passivator for traps (Tsao, S.W., et al., 2010. Hydrogen-induced improvements in electrical characteristics of a-IGZO thin-film transistors. Solid-State Electron, 54, pp.1497-1499). In this study, In-Situ hydrogen plasma is applied to deposit IGZO channel. With atmospheric-pressure PECVD (AP-PECVD), IGZO thin film can be deposited without vacuum system, large area manufacturing, and cost reducing (Chang, K.M., et al., 2011. Transparent conductive indium-doped zinc oxide films prepared by atmospheric pressure plasma jet. Thin Solid Films, 519, pp.5114-5117). The results show that with appropriate flow ratio of Ar/H-2 plasma treatment, the a-IGZO TFT device exhibits better performance with mobility (mu(FE)) 19.7 cm(2)/V.S, threshold voltage (V-T) 1.18 V, subthreshold swing (SS) 81 mV/decade, and I-on/I-off ratio 5.35 x 10(7).
Study of In-Situ Hydrogen Plasma Treatment on InGaZnO with Atmospheric Pressure-Plasma Enhanced Chemical Vapor Deposition
(2019-04-01)
Wu, Chien-Hung
;
Chang, Kow-Ming
;
Chen, Yi-Ming
;
Zhang, Yu-Xin
;
Tan, Yu-Hsuan
In the past few years, thin film transistors have a wide range of applications on display technology, material selection and quality for its active layer is critical for device performance. Traditional amorphous silicon (a-Si) silicon has a lot of advantages such as good productivity, short process and low-cost. It also has a lot of shortcomings on these applications on TFTs such as photosensitivity, light degradation, and opacity, etc. The dispute of the material based on a-Si: H as an active layer in TFT is low field effect mobility (similar to 1 cm(2)/V.S) (M. Shur and M. Hack, J. Appl. Phys. 55, 3831 (1984)), photo sensitivity (low band gap about 1.7 V) and high deposition temperature (similar to 400 degrees C) (M. Shur, et al., J. Appl. Phys. 66, 3371 (1989); K. Khakzar and E. H. Lueder, IEEE Trans. Electron Devices 39, 1438 (1992)). Amorphous In-Ga-Zn-O (IGZO) had attracted attention that compared with the conventional a-Si: H, due to its good properties of simultaneously high/low conductivity with high visual transparency via doping level. Oxide-based semiconductors, such as ZnO (G. Adamopoulos, et al., Appl. Phys. Lett. 95, 133507-3 (2009); H.-C. Cheng, et al., Appl. Phys. Lett. 90, 012113-3 (2007)) and IGZO (C. J. Chiu, et al., Electron Device Letters, IEEE 31, 1245 (2010); L. Linfeng and P. Junbiao, IEEE Transactions on Electron Devices 58, 1452 (2011)) have been reported for the active channel layer. These oxide-based materials offer good electrical properties and high transparency for thin film transistors, its high transmittance can be applied to fabricate the full transparent TFT on flexible substrate. With In-situ hydrogen plasma treatment on a-IGZO produced by atmospheric pressure-plasma enhanced chemical vapor deposition (AP-PECVD), the material characteristics of a-IGZO is studied.
The Effect of Microwave Annealing of Reliability Characteristics on Amorphous IGZO Thin Film Transistors
(2019-04-01)
Wu, Chien-Hung
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Chang, Kow-Ming
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Chen, Yi-Ming
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Zhang, Yu-Xin
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Cheng, Chia-Yao
Amorphous oxide semiconductors (AOSs) are attracted much attention due to high mobility, low temperature deposition, flexible, transmission, and uniformity. The thin film transistors (TFTs) with a-IGZO thin film as active layer perform higher field-effect mobility (>10 cm(2)/V . S), larger I-on/I-off ratio (>10(6)), smaller subthreshold swing and better stability against electrical stress. LaAlO3/ZrO2 is employed as gate electrode and gate dielectric layer for a-IGZO TFTs, under the premise that performance of a-IGZO TFTs without decreasing. Due to the good selectivity of energy transformation and rapid heating rate, microwave annealing is applied to improve the device reliability in the investigation. With adjusting the parameter of microwave annealing, the effect on reliability characteristics of a-IGZO TFTs is studied.
The Investigation for In-Ga-Zn-O TFTs with Post Deposition of in-situ Ar/H-2 Plasma Treatment by Atmospheric Pressure Plasma Jet
(2016)
Chang, Kow-Ming
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Huang, Bo-Wen
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Wu, Chien-Hung
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Chen, Hsin-Ying
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Zheng, You-Xian
Atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) was applied for the fabrication of amorphous indium gallium zinc oxide thin-film transistors (a-IGZO TFTs). In this work, a-IGZO TFTs fabricated by AP-PECVD technique were firstly treated by post deposition of in-situ Ar/H-2 plasma with atmospheric pressure plasma Jet (APPJ). Compared to without plasma treatment, samples with the post in-situ Ar/H-2 plasma treatment on IGZO active layer exhibited higher mobility of 20.12 cm(2)/V.S, V-T of 1.11 V, lower subthreshold swing of 93 mV/decade, higher I-on/I-off of 5.34x10(7). The excellent IGZO TFTs fabricated by AP-PECVD technique also show highly transparent characteristics.
Using KrF ELA to Improve Gate-Stacked LaAlO3/ZrO2 Indium Gallium Zinc Oxide Thin-Film Transistors with Novel Atmospheric Pressure Plasma-Enhanced Chemical Vapor Deposition Technique
(2018-03-01)
Wu, Chien-Hung
;
Chang, Kow-Ming
;
Chen, Yi-Ming
;
Huang, Bo-Wen
;
Zhang, Yu-Xin
Atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) technique and KrF excimer laser annealing (ELA) were employed for the fabrication of indium gallium zinc oxide thin-film transistors (IGZO-TFTs). Device with a 150 mJ/cm(2) laser annealing densities demonstrated excellent electrical characteristics with improved on/off current ratio of 4.7x10(7), high channel mobility of 10 cm(2)/V-s, and low subthreshold swing of 0.15 V/dec. The improvements are attributed to the adjustment of oxygen vacancies in the IGZO channel to an appropriate range of around 28.3% and the reduction of traps at the high-k/IGZO interface.