Hisayuki Kato
Hitachi
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Publication
Featured researches published by Hisayuki Kato.
Journal of Applied Physics | 1990
Yoshiaki Kamigaki; Shinichi Minami; Hisayuki Kato
Trap centers in amorphous silicon nitride (a‐SiNx) have been considered to be amphoteric. We found two signals of Si3 3/4 Si0 and N3 3/4 Si0 (Si dangling bonds with an unpaired electron) by an electron‐spin‐resonance method, and estimated the hole trap density to be larger than the electron trap density by about one decade, using the nonvolatile memory devices. As a result, we propose a new portrayal in which electron/hole traps are at the interface between Si clusters and a‐SiNx bulk, and hole traps are at nitrogen vacancies in a‐SiNx bulk.
Ferroelectrics | 1999
Kiyoshi Ogata; Kazufumi Suenaga; Kazuhiko Horikoshi; Keiichi Yoshizumi; Hisayuki Kato; Mitsuhiro Mori
Abstract The effect of grain size on electric properties has been investigated. Various (111) oriented PLZT films were prepared using the RF magnetron sputtering method on Pt/Ti/SiO2/Si substrates. Grain size and surface roughness were observed by AFM. The results showed that; 1) surface roughness depends on average grain size and 2) decreasing grain size decreases process degradation and fatigue. The grain boundary was thought to be responsible for process damage, such as reduction by hydrogen, at electrode interface tops. Electric field strength at grain boundaries also increased with increases in surface roughness.
Japanese Journal of Applied Physics | 1993
Noriaki Honma; Hisayuki Kato
Charge density uniformities in an as-deposited silicon nitride film are evaluated using an ac photovoltaic method. The experimental results for photovoltages as a function of the thickness of a silicon nitride film showed that the net charge in silicon nitride is positive, and a negative charge is located near the interface between the silicon nitride and the ultrathin oxide on the silicon substrate. The photovoltages also greatly varied when the gas flow ratio of NH3 to SiH2Cl2 is changed from 5 to 50 while keeping the thickness constant. The ac photovoltaic measurement revealed a charge density inhomogeneity of 8-nm-thick silicon nitride films, which is attributed to local variations of the gas flow ratio.
Archive | 1995
Hideo Miura; Shunji Moribe; Hisayuki Kato; Atsuyoshi Koike; Shuji Ikeda; Asao Nishimura
Archive | 2001
Kazufumi Suenaga; Kiyoshi Ogata; Kazuhiko Horikoshi; Jun Tanaka; Hisayuki Kato; Keiichi Yoshizumi; Hisahiko Abe
Archive | 2001
Kiyoshi Ogata; Kazuhiko Horikoshi; Kazufumi Suenaga; Hisayuki Kato; Keiichi Yoshizumi; Masahito Yamazaki
Archive | 2001
Kiyoshi Ogata; Kazuhiko Horikoshi; Kazufumi Suenaga; Hisayuki Kato; Keiichi Yoshizumi; Masahito Yamazaki
Archive | 1997
Kiyoshi Ogata; Kazuhiko Horikoshi; Kazufumi Suenaga; Hisayuki Kato; Keiichi Yoshizumi; Masahito Yamazaki
Archive | 1995
Hideo Miura; Shunji Moribe; Hisayuki Kato; Atsuyoshi Koike; Shuji Ikeda; Asao Nishimura
Archive | 1995
Hideo Miura; Shunji Moribe; Hisayuki Kato; Atsuyoshi Koike; Shuji Ikeda; Asao Nishimura