Browsing by Author "Fuyuki, Takashi"

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Controlled Reduction of Bionanodots for Better Charge Storage Characteristics of Bionanodots Flash Memory
(2009-04-01)
Tojo, Yosuke
;
Miura, Atsushi
;
Uraoka, Yukiharu
;
Fuyuki, Takashi
;
Yamashita, Ichiro
We proposed a new process technology, named the "bio-nano-process", in which semiconductor processing technology and biotechnology are conbined. We utilized a ferritin protein cobalt core as a memory node, and succeeded in performing the operation of floating gate memory. In this study, we undertook the reduction control of a cobalt core embedded in silicon oxide by thermal annealing. We also fabricated metal-oxide-semiconductor (MOS) capacitors with using the cobalt core and evaluated their electronic properties. As a result, we could elucidate the contribution of the metallic cobalt in the core by controlling of the ambient and temperature. We found that memory windows become large with increasing contribution of metallic cobalt. (C) 2009 The Japan Society of Applied Physics
Nonvolatile Flash Memory Based on Biologically Integrated Hierarchical Nanostructures
(2013-10-08)
Sano, Ken-Ichi
;
Miura, Atsushi
;
Yoshii, Shigeo
;
Okuda, Mitsuhiro
;
Fukuta, Megumi
The first six peptides of multifunctional titanium binding peptide-1 bestowed recombinant L-ferritin, minT1-LF, was genetically engineered and used to fabricate multilayered nanoparticle architecture. The multifunctionality of minT1-LF enables specific binding of nanoparticle-accommodated minT1-LF to the silicon substrate surface and wet biochemical fabrication of gate oxide layer by its biomineralization activity. Three-dimensional (3D) nanoparticle architecture with multilayered structure was fabricated by the biological layer-by-layer method and embedded in a metal oxide-semiconductor device structure as a charge storage node of a flash memory device. The 3D-integrated multilayered nanoparticle architecture successfully worked as a charge storage node in flash memory devices that exhibited improved charge storage capacity compared with that of a conventional monolayer structure device.
The characterization of a single discrete bionanodot for memory device applications
(2009-03-25)
Miura, Atsushi
;
Tanaka, Ryota
;
Uraoka, Yukiharu
;
Matsukawa, Nozomu
;
Yamashita, Ichiro
We investigated electronic properties of a biochemically synthesized cobalt oxide bionanodot (Co-BND) by means of scanning tunneling microscopy/spectroscopy (STM/STS) and Kelvin-probe force microscopy (KFM). Experimentally obtained I-V characteristics and numerically obtained dI/dV and (dI/dV)/(I/V) from I-V revealed the band gap energy, band position of valence and conduction band of the Co-BND. KFM observation shows that bias polarity dependent surface potential change after charge injection. The observed surface potential change indicates that the Co-BND has a charge storage capability. We demonstrated the application of Co-BNDs for electronic devices by choosing flash memory as the example device. The fabricated Co-BND embedded MOS memory showed clear memory operation due to the charge confinement in the embedded Co-BNDs.