Patents by Inventor Mitsuo Harata
Mitsuo Harata has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5517445Abstract: A non-volatile semiconductor memory device, includes a memory cell having a capacitor formed by stacking a semiconductor layer and a ferroelectric layer between a pair of electrodes, the semiconductor layer and the ferroelectric layer forming a semiconductor-ferroelectric junction, a writing circuit in which a voltage higher than a coercive electric field of the ferroelectric material is applied to the capacitor of the memory cell to align a polarization direction of the ferroelectric layer in a predetermined direction so as to set a capacitance of the capacitor at a predetermined value, thereby writing data corresponding to the predetermined value of the capacitance, and a reading circuit in which a voltage less than the coercive electric field of the ferroelectric layer is applied to the capacitor of the memory cell in which the data is written, thereby reading the data.Type: GrantFiled: October 30, 1991Date of Patent: May 14, 1996Inventors: Motomasa Imai, Kazuhide Abe, Koji Yamakawa, Hiroshi Toyoda, Yoshiko Kohanawa, Mitsuo Harata
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Patent number: 5297077Abstract: A semiconductor memory device comprises a ferroelectric capacitor, a voltage output circuit for outputting a first voltage for reversely polarizing the ferroelectric capacitor and a second voltage by which the polarization of the ferroelectric capacitor is not reversed, regardless of data stored in the ferroelectric capacitor, a first reference capacitor having a such a capacitance as to accumulate less charge than charge which the ferroelectric capacitor accumulates, when the second voltage is applied to the ferroelectric capacitor, a second reference capacitor having such a capacitance that as to accumulate greater charge than the charge which the ferroelectric capacitor accumulates while the ferroelectric capacitor is forwardly polarized, when the first voltage is applied to the ferroelectric capacitor, thus reversely polarizing the ferroelectric capacitor, a sense amplifier connected to the ferroelectric capacitor and the first or second reference capacitor, a reference-capacitor selecting circuit for conType: GrantFiled: March 28, 1991Date of Patent: March 22, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Motomasa Imai, Hiroshi Toyoda, Kazuhide Abe, Koji Yamakawa, Hisakazu Iizuka, Mitsuo Harata, Koji Sakui
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Patent number: 5182695Abstract: A ceramic composition which forms, when sintered, a dielectric having a crystal structure represented by the general formula:[Pb.sub.1-x A.sub.x ].sub.[A] (B.sub.1,B.sub.2).sub.[B] O.sub.3where A is at least one element selected from the group consisting of Ca, Sr, Ba, Ag, La and Nd, B.sub.1 is at least one element selected from the group consisting of Mg, Zn, Ni, Co, Fe, Mn and In, B.sub.2 is at least one element selected from the group consisting of Nb, W, Ta and Sb, x is 0 to 0.5, and the molar ratio of [A]/[B] is 0.995 or more, but 0.99 or less.Type: GrantFiled: August 22, 1991Date of Patent: January 26, 1993Assignees: Marcon Electronics Co., Ltde., Kabushiki Kaisha ToshibaInventors: Kiyoji Handa, Satoshi Mukaeda, Hideyuki Kanai, Yohachi Yamashita, Osamu Furukawa, Mitsuo Harata
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Patent number: 5155573Abstract: A ferroelectric capacitor includes a ferroelectric layer consisting of lead zirconate titanate formed on a silicon substrate, a plurality of rectangular trenches formed in the direction of thickness of the ferroelectric layer with a ferroelectric material therebetween, and first and second electrodes consisting of metal tungsten buried in the trenches to oppose each other with the ferroelectric material therebetween.Type: GrantFiled: December 24, 1990Date of Patent: October 13, 1992Assignee: Kabushiki Kaisha ToshibaInventors: Kazuhide Abe, Hiroshi Toyoda, Koji Yamakawa, Motomasa Imai, Mitsuo Harata, Koji Sakui
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Patent number: 5059566Abstract: A high-dielectric constant ceramic composite is provided in which an appropriate amount of glass component is added to a composite of the BaTiO.sub.3 -PbMO.sub.3 group having a low temperature coefficient in the dielectric constant thereof. The added glass component serves to maintain the satisfactory properties of the ceramic composite even after various types of reliability tests.Type: GrantFiled: December 27, 1989Date of Patent: October 22, 1991Assignee: Kabushiki Kaisha ToshibaInventors: Hideyuki Kanai, Yohachi Yamashita, Osamu Furukawa, Mitsuo Harata
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Patent number: 4882652Abstract: When a portion of the Pb of a Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 -based ceramic composition within the region bounded by lines connecting a, b, c, d, e and f points in the ternary composition diagram of the accompanying FIG. 1 is substituted by a small amount of Ca, a high dielectric constant type ceramic composition is obtained which has a small temperature coefficient of dielectric constant and which is effective as a material for multilayer ceramic capacitors.Type: GrantFiled: November 2, 1987Date of Patent: November 21, 1989Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Furukawa, Mitsuo Harata, Takaaki Yasumoto, Motomasa Imai
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Patent number: 4818736Abstract: When a portion of the Pb of a Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 -based ceramic composition within the region bounded by lines connecting a, b, c and d points in the ternary composition diagram of the accompanying FIG. 1 is substituted by a small amount of Ba and/or Sr, a high dielectric constant type ceramic composition which has a small temperature coefficient of dielectric constant and which is effective as a material for multilayer ceramic capacitors is obtained.Type: GrantFiled: February 11, 1988Date of Patent: April 4, 1989Assignee: Kabushiki Kaisha ToshibaInventors: Yohachi Yamashita, Osamu Furukawa, Mitsuo Harata, Takashi Takahashi
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Patent number: 4772985Abstract: Disclosed is a thick film capacitor comprising (a) a sintered layer of a ferroelectric material mainly consisting of one or more ferroelectric inorganic compounds having a perovskite structure and an inorganic binder having a eutectic composition which experiences a liquid phase at a temperature lower than the sintering temperature of the ferroelectric inorganic compounds, and (b) at least two electrodes formed on both surfaces of the sintered layer of the ferroelectric material. In the thick film capacitor of this invention, the perovskite structure of the ferroelectric inorganic compounds is not destroyed upon sintering. Therefore, a high degree of sintering, a good dielectric characteristic and high moisture and migration resistances can be obtained.Type: GrantFiled: September 18, 1987Date of Patent: September 20, 1988Assignee: Kabushiki Kaisha ToshibaInventors: Takaaki Yasumoto, Osamu Furukawa, Nobuo Iwase, Mitsuo Harata, Masao Segawa
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Patent number: 4767732Abstract: To obtain a ceramic material having a high dielectric constant (K=2300 to 7000), a high insulation resistance (CR=4000 to 18000 ohmF), a low temperature dependence (.+-.10%) to (.+-.22, -33%) upon dielectric constant over a wide temperature range (-55 and +125.degree. C.) and a relatively low sintering temperature (1000.degree. C. to 1250.degree. C.), BaTiO.sub.3 powder at least 50 wt % of which is 0.7 to 3 .mu.m in particle size) is mixed with another compound with perovskite structure mainly composed of oxides of Pb, Ba, Sr, Zn, Nb, Mg and Ti before sintering. Further, part of Ti of BaTiO.sub.3 is substitutable with Zr or Sn, and part of Ba of BaTiO.sub.3 is substitutable with Sr, Ca or Ce.Type: GrantFiled: August 28, 1987Date of Patent: August 30, 1988Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Furukawa, Seiichi Yoshida, Motomasa Imai, Mitsuo Harata
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Patent number: 4701767Abstract: A method is disclosed which manufactures a recording head adapted to be moved relative to a recording medium, which is comprised of a conductive substrate and dielectric layer formed on the conductive substrate, to permit data to be recorded on the recording medium with the use of a conductive/magnetic toner on the recording medium. A conductive/magnetic sheet is attached to an insulating substrate of a first size with an adhesive layer therebetween, the first size of the insulating substrate is greater than a second size thereof defined by an insulating substrate of a finally completed recording head. The conductive/magnetic sheet is selectively etched to form an array of slits at a predetermined interval with both ends of the slits located beyond the side edges of an insulating substrate of a finally completed recording head. At one side edge portion of the conductive/magnetic sheet the conductive/magnetic sheet is electroplated to form a plated layer for a bonding pad.Type: GrantFiled: June 5, 1986Date of Patent: October 20, 1987Assignee: Kabushiki Kaisha ToshibaInventors: Motomasa Imai, Mitsuo Harata, Takashi Takahashi, Kazuo Nishijima
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Patent number: 4574292Abstract: In a thermal head having a substrate and a heating resistor of thin film type formed thereon, the heating resistor is a deposited metal oxide film essentially consisting of ruthenium oxide and an oxide of at least one metal M selected from the group consisting of Ca, Sr, Ba, Pb, Bi and Tl. The deposited metal oxide film has an atomic ratio M/Ru of the metal M to ruthenium of 0.6 to 2.Type: GrantFiled: November 27, 1984Date of Patent: March 4, 1986Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Takikawa, Mitsuo Harata