Browsing by Author "Berling, Dominique"

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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.
Deep ultraviolet laser direct write for patterning sol-gel InGaZnO semiconducting micro/nanowires and improving field-effect mobility
(2015-05-27)
Lin, Hung-Cheng
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Stehlin, Fabrice
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Soppera, Olivier
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Zan, Hsiao-Wen
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Li, Chang-Hung
Deep-UV (DUV) laser was used to directly write indium-gallium-zinc-oxide (IGZO) precursor solution and form micro and nanoscale patterns. The directional DUV laser beam avoids the substrate heating and suppresses the diffraction effect. A IGZO precursor solution was also developed to fulfill the requirements for direct photopatterning and for achieving semi-conducting properties with thermal annealing at moderate temperature. The DUV-induced crosslinking of the starting material allows direct write of semi-conducting channels in thin-film transistors but also it improves the field-effect mobility and surface roughness. Material analysis has been carried out by XPS, FTIR, spectroscopic ellipsometry and AFM and the effect of DUV on the final material structure is discussed. The DUV irradiation step results in photolysis and a partial condensation of the inorganic network that freezes the sol-gel layer in a homogeneous distribution, lowering possibilities of thermally induced reorganization at the atomic scale. Laser irradiation allows high-resolution photopatterning and high-enough field-effect mobility, which enables the easy fabrication of oxide nanowires for applications in solar cell, display, flexible electronics, and biomedical sensors.
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.
Near-Infrared Laser-Annealed IZO Flexible Device as a Sensitive H2S Sensor at Room Temperature
(2020-06-03)
Chang, Po-Yi
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Lin, Ching-Fu
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Rouphael, Samer El Khoury
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Huang, Ting-Hsuan
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Wu, Chang-Mao
A metal-oxide material (indium zinc oxide [IZO]) device with near-infrared (NIR) laser annealing was demonstrated on both glass and bendable plastic substrates (polycarbonate, polyethylene, and polyethylene terephthalate). After only 60 s, the sheet resistance of IZO films annealed with a laser was comparable to that of thermal-annealed devices at temperatures in the range of 200-300 degrees C (1 h). XPS, ATR, and AFM were used to investigate the changes in the sheet resistance and correlate them to the composition and morphology of the thin film. Finally, the NIR-laser-annealed IZO films were demonstrated to be capable of detecting changes in humidity and serving as a highly sensitive gas sensor of hydrogen sulfide (in ppb concentration), with room-temperature operation on a bendable substrate.