Materials Science and Engineering Colloquium
Date: October 03, 2014 from 11:00 am to 12:00 pm EDT
Location: Columbia University, Morningside Campus
S.W. Mudd, Room 214
Contact: For further information regarding this event, please contact James Im by sending email to or by calling 212-854-8341.
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Prof. Seiichiro Higashi
Hiroshima University

"Atmospheric Pressure Plasma Processing and Layer Transfer Technique for Thin-Film Device Fabrication on Glass and Plastic Substrates"

Abstract: Crystalline growth from melt during micro-thermal-plasma-jet (μ-TPJ) irradiation to amorphous silicon (a-Si) film has been directly observed by high-speed camera. Long lateral growth perpendicular to the oval-shaped liquid-solid interface results in formation of random grain boundaries (GBs). Introduction of strip pattern markedly reduces random GBs and enables single-crystalline growth at predetermined channel regions. N- and p-channel thin-film transistors (TFTs) showed high performance and small characteristic variability, and operation of 8-bit shift register at a supply voltage of 5V with the clock frequency of 50 MHz has been achieved. In addition, we propose a local layer transfer technique utilizing meniscus force of water, which enables formation of single-crystalline silicon (100) layer on glass and polyethylene terephthalate (PET) substrates. High mobility TFTs of 1076 and 609 cm2V-1s-1, respectively, have been successfully fabricated on each substrate.

Biography: Professor Higashi received the B.S. and M.S. degrees of physics from Kyushu University, in 1989 and 1991, respectively. He received the Ph.D. degree of electrical engineering from Tokyo University of Agriculture and Technology in 2001.

He joined Seiko Epson Corporation in 1992 and he designed driver-integrated high definition liquid crystal display (LCD) panels for projectors. Then he involved in development of low-temperature processed polycrystalline silicon thin-film transistor (poly-Si TFT) for large area applications. He was a group leader for the researches of excimer laser crystallization of amorphous silicon films, formation of high quality gate SiO2 films by PECVD, and process integration for high performance poly-Si TFT fabrication.

He joined Hiroshima University in 2003 and has developed a novel crystallization technique using atmospheric pressure thermal plasma jet (TPJ). This rapid annealing technique has been applied to TFT fabrication and a high mobility of 520 cm2V-1s-1 and CMOS operation have been achieved. He also invented noncontact temperature measurement technique with millisecond time resolution using a probe laser. These techniques have been applied to impurity activation for ultra shallow junction (USJ) formation, densification of low-temperature-deposited SiO2 films, and formation of silicon nanocrystals embedded in SiO2 matrix for non-volatile memory applications. More recently, he has proposed a novel layer transfer technique of single-crystalline Si to plastic substrates utilizing meniscus force of water. His group has succeeded fabrication of TFTs on PET substrate with a record mobility of 609 cm2V-1s-1 under 130C process. He authored and coauthored more than 100 papers.

Host: James Im

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