Browsing by Author "Yeh, Chun-Cheng"

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Achieving High Field-Effect Mobility in Amorphous Indium-Gallium-Zinc Oxide by Capping a Strong Reduction Layer
(2012-07-10)
Zan, Hsiao-Wen
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Yeh, Chun-Cheng
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Meng, Hsin-Fei
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Tsai, Chuang-Chuang
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Chen, Liang-Hao
Chemical and structural investigation of zinc-oxo cluster photoresists for DUV lithography
(2017-03-14)
Yeh, Chun-Cheng
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Liu, Hung-Chuan
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Heni, Wajdi
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Berling, Dominique
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Zan, Hsiao-Wen
Metal oxo cluster photoresists have drawn a lot of attention in recent years due to their interesting properties combining the advantages of both inorganic and organic features. Their organic functionalities offer the possibility of patterning them by photon or electron beam lithography into metal oxide micro or nanostructures. Thanks to the inorganic metal oxide frameworks, these patterns show higher etch resistance and refractive index in the visible light range than neat organic patterns. Moreover, the nanosize of the photoresist building blocks makes them suitable for high resolution lithography. To have an in-depth understanding of the effect of physicochemical parameters on the size, shape and physical properties of photo-patterned structures, a detailed investigation was carried out on a zinc-oxo cluster photoresist combined with deep ultraviolet (DUV) lithography. The results show the impact of both DUV irradiation and thermal treatment on material patterning. The impact of crystallization is particularly discussed since it has a strong influence on the shape of patterns.
Controllable Formation of Zinc Oxide Micro- and Nanostructures via DUV Direct Patterning
(2016-10-06)
Yeh, Chun-Cheng
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Liu, Hung-Chuan
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Chuang, Ming-Yen
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Denzer, Joseph
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Berling, Dominique
Various kinds of zinc oxide (ZnO) nanostructures, such as ZnO nanowires, ZnO nanobelts, ZnO nanosheets, and ZnO nanorods are promising building blocks for nanoscale systems. However, to precisely control the size, shape, and to make a controlled assembly of synthesized ZnO nanostructures are major difficulties in the development of bottom-up devices. To overcome the challenge regarding reproducibility and positioning, a new method is proposed, deep ultra-violet (DUV) direct photo-patterning, to create ZnO micro- and nanostructures. A sol-gel formulation sensitive to DUV light and based on zinc methacrylate precursor is developed, and the photoreactions of zinc methacrylate under DUV light are carefully investigated by in situ spectroscopic ellipsometry, in situ FTIR, and XPS analysis. Then, the sol-gel solution is used as a negative tone resist in DUV lithography to evaluate its performance in producing high-resolution patterns. The results indicate that small patterns from micro-to nanoscale can be obtained in a simple and direct way.
Nanoscale Ferromagnetic Cobalt-Doped ZnO Structures Formed by Deep-UV Direct-Patterning
(2017-11-23)
Yeh, Chun-Cheng
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Colis, Silviu
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Fioux, Philippe
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Zan, Hsiao-Wen
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Berling, Dominique
Cobalt (II) acetate is mixed with zinc methacrylate (ZnMAA) to form a photopatternable Co-doped zinc oxide precursor. By using deep-UV (DUV) interference lithography, Co-doped ZnMAA precursor can be patterned as negative tone resist and transformed into ferromagnetic Co:ZnO films after thermal treatment. Moreover, Co:ZnO patterns as small as 300 nm line-width can be easily obtained. To have an in-depth understanding to the effect of DUV-patterning process as well as thermal annealing on Co:ZnO films derived from Co-doped ZnMAA precursor, optical, magnetic, and electrical characterizations are performed on Co:ZnO films prepared in different conditions. For the Co:ZnO film prepared without DUV-patterning, large zero-field-cooling (ZFC)-field-cooling (FC) irreversibility appears in superconducting quantum interference device measurements after vacuum annealing, indicating that Co clusters have formed inside the film. On the other hand, no ZFC-FC bifurcation can be observed for the DUV-patterned Co:ZnO film after the vacuum annealing, suggesting that the uniformity of Co ion distribution inside ZnO lattice is improved by DUV-patterning.
Room-temperature-operated sensitive hybrid gas sensor based on amorphous indium gallium zinc oxide thin-film transistors
(2011-06-20)
Zan, Hsiao-Wen
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Li, Chang-Hung
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Yeh, Chun-Cheng
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Dai, Ming-Zhi
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Meng, Hsin-Fei
An organic sensing layer is capped onto an amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) to form a hybrid sensor. The organic layer, served as a second gate, forms a p-n junction with the a-IGZO film. Oxidizing or reducing vapor molecules act like electron acceptors or electron donors to change the potential of the organic layer and the current of a-IGZO TFT. A sensitive and reversible response to 100 ppb ammonia and 100 ppb acetone is obtained at room temperature. This letter opens a route to develop low-cost large-area bio/chemical sensor arrays based on the emerging a-IGZO TFT technology. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601488]
Solution-Based Micro- and Nanoscale Metal Oxide Structures Formed by Direct Patterning for Electro-Optical Applications
(2018-12-13)
Yeh, Chun-Cheng
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Zan, Hsiao-Wen
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Soppera, Olivier
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光電工程學系
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光電工程研究所
Due to their transparency and tunable electrical, optical, and magnetic properties, metal oxide thin films and structures have many applications in electro-optical devices. In recent years, solution processing combined with direct-patterning techniques such as micro-/nanomolding, inkjet printing, e-jet printing, e-beam writing, and photopatterning has drawn much attention because of the inexpensive and simple fabrication process that avoids using capital-intensive vacuum deposition systems and chemical etching. Furthermore, practical applications of solution direct-patterning techniques with metal oxide structures are demonstrated in thin-film transistors and biochemical sensors on a wide range of substrates. Since direct-patterning techniques enable low-cost fabrication of nanoscale metal oxide structures, these methods are expected to accelerate the development of nanoscale devices and systems based on metal oxide components in important application fields such as flexible electronics, the Internet of Things (IoT), and human health monitoring. Here, a review of the fabrication procedures, advantages, limitations, and applications of the main direct-patterning methods for making metal oxide structures is presented. The goal is to highlight the examples with the most promising perspective from the recent literature.