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Tatsuya Shimoda Professor
School of Materials Science¡¢Energy and Environment Area
B.S. from The University of Tokyo(1977), Ph.D from The University of Tokyo(1987)
Magnetic Material, Electronics Devices, Organic Devices, Micro Liquid Process
Flexible Devices, Thin Film Transistor, Organic EL, Organic TFT, Inkjet Method
Study for direct fabrication of electronics devices by using functional liquids and systematization of the related topics
Although progress of high-tech devices is prominent,one key area lags behind¡½the efficient use of energy and materials in the manufacturing process. The yield of the enormous vacuum devices used in the fabrication of thin films under the CVD and PVD (chemical and physical vapor deposition) methods is a prime example. The proportion of source material that ends up deposited on the substrate is less than 10%, and most of this material is then etched away during the photolithography process. When the entire fabrication process is complete, therefore, less than 1% of the original source material is left.
In order to solve some of these problems. We proposed a new process called the ¡Èmicro-liquid process,¡É which uses inkjet technology or LSMCD method to directly fabricate electronic devices from functional liquids that serve as the thin films. The micro-liquid process is a methodology for fabricating electronic devices with the smallest possible amount of material accumulated on wafers. Already many organic and inorganic thin films and devices have been developed using inkjet technology as a deposition and patterning tool.
The materials used in the micro-liquid process are functional liquids that can be converted to semiconductors, insulators, and metallic thin films. Development of these precursor solutions has been the first research subject. Organic LEDs and organic transistors can be fabricated using functional polymer liquid. Many first-rate liquid metals that can be converted to metallic thin films have been developed. Now even liquid silicon material is also available.
The second research subject is deposition and patterning of micro-liquids. At the micro scale, surface forces are hundreds to thousands of times stronger than gravitational forces. If surface energy cannot be controlled precisely, it is impossible to even make a straight line. Once we learned how to control surface forces, however, precision in the micro-liquid process becomes greater than in conventional printing technology by over a factor of ten. To control the degree of the surface energy on the substrate, we created lyophilic and lyophobic areas so that the liquid applied would spontaneously collect in the lyophilic area, thereby achieving precision at the submicron level.
The third research subject is the spontaneous transport of solute while the liquid is drying. Because the surface area per volume of microdroplets is relatively large compared to that of macroscopic counterpart, drying is extremely rapid. When the liquid dries with its edges fixed in place, a microscopic flow of fluid moves from the center to the edge, thereby transporting solute to the edges. To control this phenomenon is essential.
By using micro liquid process, devices which have a dimension from several micro-meters to several dozen micro-meters can be fabricated. When you try to make a device having a size less than several dozen nano-meters, however, it becomes impossible to use inkjet technology. Because, the droplet size of inkjet is more than several micro-meters. For fabrication of nano-sized devices should be utilized to deposit solutions spontaneously on the defined nano area. The process which we call ¡Ènano liquid process¡É is a research theme collaborated with ERATO project conducted Japan Science and Technology Agency The microdroplets.
- Evaporation of an inkjet droplet on a flat substrate¡¤
T. Masuda and T. Shimoda¡¤
Japnese Journal of Applied Physics¡¤56¡¤016701¡¤2017
- Highly conductive ruthenium oxide thin films by a low-temperature solution process and greenlaser annealing¡¤Y. Murakami, J.Li and T.Shimoda¡¤Materials Letters 121-124¡¤152¡¤2015¡¤15/03/26
- Solution processing of highly conductive ruthenium and ruthenium oxide thin films from¡¡ruthenium¨Camine complexes¡¤Y. Murakami, J. Li, D. Hirose, S. Kohara and¡¡T. Shimoda,¡¤J. Mater. Chem. C, 2015, 3, 4490¨C4499¡¤2015/04
¡þLectures and Presentations
- Development of a Patterning Method of Oxide Materials by UV Irradiation and Selective Removal Using Solvent¡¤Yuuki Yoshimoto, Tatsuya Shimoda¡¤5th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO 2015), P1-16, June 16-19 ,Niigata, Japan¡¤Niigata, Japan¡¤June 16-19, 2015
- Amorphous silicon nano pillars using silicon precursor solution by nanoimprint technology¡¤
Ken Yamazaki, Takashi Masuda, and Tatsuya Shimoda¡¤
The 5th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO 2015)¡¤Niigata, Japan¡¤June 16-19, 2015
- Fine Pattern of Highly Conductive Amorphous LaRuO by nano-Rheology Printing Method¡¤Koji Nagahara, Jinwang Li, and Tatsuya Shimoda¡¤The 5th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO 2015) P2-34,, June 16-19, 2015, TOKI MESSE Niigata Convention Center, Niigata, Japan,¡¤Niigata, Japan¡¤June 16-19, 2015
¢£Academic Awards Received
- SID 2014 International Symposium, Distiguished Poster Award¡¤Society Information Display