|マテリアル研究棟MS Building ＩＶ 5F
Tatsuya Shimoda Professor
School of Materials Science（Department of Materials Science・Materials Characterization and Device）
B.S. from The University of Tokyo(1977), Ph.D from The University of Tokyo(1987)
Researcher at development department of SEIKO EPSON（1977）、Department chief at basic development department IS group of SEIKO EPSON（1985）、Department manager at functional materials research development of SEIKO EPSON（1989）、Director at fundamental technology research institute of SEIKO EPSON（1996）、Consulting Director of Cambridge research institute of SEIKO EPSON（1998）、Fellow (administration officer ) of SEIKO EPSON（2002）、Deputy Director-General of development headquarter of SEIKO EPSON（2004）、In charge of developmental technique strategyoffice as Felow of SEIKO EPSON（2006）
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―the 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 “micro-liquid process,” 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 “nano liquid process” is a research theme collaborated with ERATO project conducted Japan Science and Technology Agency The microdroplets.
- Effect of Annealing and Hydrogen Radical Treatment on the Structure of Solution-Processed Hydrogenated Amorphous Silicon Films，Y. Sakuma, K. Ohdaira, T. Masuda, H. Takagishi, Z. Shen, and T. Shimoda，Jpn. J. Appl. Phys. (in press)
- Single-grain Si thin-film transistors on flexible polyimide substrate fabricated from doctor-blade coated liquid-Si，J. Zhang, M. Trifunovic, M. van der Zwan, H. Takagishi, R. Kawajiri, T. Shimoda,C. I. M. Beenakker, and R. Ishihara，APPLIED PHYSICS LETTERS，102，243502，2013/06/18
- Interface Charge Trap Density of Solution Processed Ferroelectric Gate Thin Film Transistor Using ITO/PZT/Pt Structure，Pham Van Thanh , Bui Nguyen Quoc Trinh , Takaaki Miyasako , Phan Trong Tue , Eisuke Tokumitsu and Tatsuya Shimoda，Ferroelectrics Letters Section， 40:1-3，17-29，2013/08/13
◇Lectures and Presentations
- Ink-Jet Printed Thermoelectric Module，Mikio Koyano, Yojiro Maeda, Koichiro Suekuni, Go Nakamoto, Hideo Iwasaki, Tatsuya Shimoda, Tetsushi Tanaka, Katsushi Fukuda, Hirokuni Hachiuma, Seijiro Sano, Makio Kurisu，The 32nd International Conference on Thermoelectrics (ICT2013), June 30 to July 4, 2013, Kobe, JAPAN，Kobe, JAPAN，2013/07/04
- Amorphous Silicon Solar Cell by Silicon In，Takashi Masuda and Tatsuya Shimoda，International Device Physics Young Scientist Symposium (IDYS) 2013, March 4, 2013, Nara Institute of Science and Technology, JAPAN，Nara, Japan，2013/03/04
- Past and future of device printing，T. Shimoda，The 4th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO 2013), June 17-20(2013), Kanazawa, Japan，Kanazawa, Japan，2013/06/17-20