Patents by Inventor Juro Mita

Juro Mita 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).

  • Patent number: 8202794
    Abstract: The contact resistance between an Ohmic electrode and an electron transit layer is reduced compared with a case in which the Ohmic electrode is provided to a depth less than the heterointerface. As a result, for an Ohmic electrode provided in a structure comprising an electron transit layer formed of a first semiconductor layer formed on a substrate, an electron supply layer comprising a second semiconductor layer forming a heterojunction with the electron transit layer and having a smaller electron affinity than the first semiconductor layer, and a two-dimensional electron layer induced in the electron transit layer in the vicinity of the heterointerface, the end portion of the Ohmic electrode is positioned in the electron transit layer in penetration into the electron supply layer at a depth equal to or greater than the heterointerface.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: June 19, 2012
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Juro Mita, Katsuaki Kaifu
  • Publication number: 20110189826
    Abstract: The contact resistance between an Ohmic electrode and an electron transit layer is reduced compared with a case in which the Ohmic electrode is provided to a depth less than the heterointerface. As a result, for an Ohmic electrode provided in a structure comprising an electron transit layer formed of a first semiconductor layer formed on a substrate, an electron supply layer comprising a second semiconductor layer forming a heterojunction with the electron transit layer and having a smaller electron affinity than the first semiconductor layer, and a two-dimensional electron layer induced in the electron transit layer in the vicinity of the heterointerface, the end portion of the Ohmic electrode is positioned in the electron transit layer in penetration into the electron supply layer at a depth equal to or greater than the heterointerface.
    Type: Application
    Filed: April 5, 2011
    Publication date: August 4, 2011
    Applicant: OKI ELECTRIC INDUSTRY CO., LTD.
    Inventors: Juro Mita, Katsuaki Kaifu
  • Patent number: 7923753
    Abstract: The contact resistance between an Ohmic electrode and an electron transit layer is reduced compared with a case in which the Ohmic electrode is provided to a depth less than the heterointerface. As a result, for an Ohmic electrode provided in a structure comprising an electron transit layer formed of a first semiconductor layer formed on a substrate, an electron supply layer comprising a second semiconductor layer forming a heterojunction with the electron transit layer and having a smaller electron affinity than the first semiconductor layer, and a two-dimensional electron layer induced in the electron transit layer in the vicinity of the heterointerface, the end portion of the Ohmic electrode is positioned in the electron transit layer in penetration into the electron supply layer at a depth equal to or greater than the heterointerface.
    Type: Grant
    Filed: August 17, 2006
    Date of Patent: April 12, 2011
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Juro Mita, Katsuaki Kaifu
  • Publication number: 20080241469
    Abstract: An etching structure includes a substrate, a to be etched filmcovering the principal surface of the substrate, and an exposure region exposing the principal surface of the substrate and obtained by removing a part of the to be etched film. A region of the to be etched film constitutes a peripheral region surrounding the exposure region. Another region of the to be etched film outside the peripheral region constitutes a flat region. The film thickness of the to be etched film increases as the distance from the exposure region increases, such that the inclination of the outline of the cross section of the to be etched film that exists within the peripheral region decreases as the distance from the exposure region increases. The to be etched film has a side wall that extends perpendicularly to the principal surface at a boundary between the peripheral region and the flat region.
    Type: Application
    Filed: May 27, 2008
    Publication date: October 2, 2008
    Applicant: OKI ELECTRIC INDUSTRY CO., LTD.
    Inventors: Katsuaki Kaifu, Juro Mita
  • Publication number: 20080176366
    Abstract: A semiconductor body includes, on a substrate, a stack of buffer layer, UID-GaN layer overlying the buffer layer, and UID-AlGaN layer overlying the UID-GaN layer. On the surface of the UID-AlGaN layer, an insulation film is deposited and patterned. An n+-GaN layer is selectively regrown directly on a region of the surface of the semiconductor body other than the insulation film using the patterned insulation film as a mask without etching the surface of the semiconductor body. A portion of the selectively regrown n+-GaN layer corresponding to a region reserved for an ohmic contact electrode is defined and the ohmic contact electrode is formed on the region. An opening exposing a region reserved for a gate electrode is defined and formed within the insulation SiO2 layer, and a gate electrode is formed in the region. An AlGaN/GaN-HEMT or MIS type of AlGaN/GaN-HEMT has lower contact resistance and uniform device characteristics.
    Type: Application
    Filed: November 13, 2007
    Publication date: July 24, 2008
    Applicant: OKI ELECTRIC INDUSTRY CO., LTD.
    Inventors: Juro Mita, Fumihiko Toda, Toshiharu Marui
  • Patent number: 7393791
    Abstract: There is provided an etching method in which a protective film existing in an etching-destined region of a substrate structure is removed by means of ICP-RIE to form an exposure region of the principal surface of the substrate. The substrate structure comprises a substrate, a protective film formed on the substrate, a photoresist layer formed on the protective film, and a hole formed throughout the photoresist layer. The hole comprises an opening formed in the photoresist layer surface and a hollow linked to the opening in the thickness direction of the photoresist layer and reaching the protective film. ICP-RIE is performed under conditions such that (1) ICP power is 20 to 100 W, (2) RIE power is 5 to 50 W, and (3) the pressure in the etching chamber is 1 to 100 mTorr.
    Type: Grant
    Filed: August 30, 2006
    Date of Patent: July 1, 2008
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Katsuaki Kaifu, Juro Mita
  • Publication number: 20070051978
    Abstract: The contact resistance between an Ohmic electrode and an electron transit layer is reduced compared with a case in which the Ohmic electrode is provided to a depth less than the heterointerface. As a result, for an Ohmic electrode provided in a structure comprising an electron transit layer formed of a first semiconductor layer formed on a substrate, an electron supply layer comprising a second semiconductor layer forming a heterojunction with the electron transit layer and having a smaller electron affinity than the first semiconductor layer, and a two-dimensional electron layer induced in the electron transit layer in the vicinity of the heterointerface, the end portion of the Ohmic electrode is positioned in the electron transit layer in penetration into the electron supply layer at a depth equal to or greater than the heterointerface.
    Type: Application
    Filed: August 17, 2006
    Publication date: March 8, 2007
    Applicant: OKI ELECTRIC INDUSTRY CO., LTD.
    Inventors: Juro Mita, Katsuaki Kaifu
  • Publication number: 20070049031
    Abstract: There is provided an etching method in which a protective film existing in an etching-destined region of a substrate structure is removed by means of ICP-RIE to form an exposure region of the principal surface of the substrate. The substrate structure comprises a substrate, a protective film formed on the substrate, a photoresist layer formed on the protective film, and a hole formed throughout the photoresist layer. The hole comprises an opening formed in the photoresist layer surface and a hollow linked to the opening in the thickness direction of the photoresist layer and reaching the protective film. ICP-RIE is performed under conditions such that (1) ICP power is 20 to 100 W, (2) RIE power is 5 to 50 W, and (3) the pressure in the etching chamber is 1 to 100 mTorr.
    Type: Application
    Filed: August 30, 2006
    Publication date: March 1, 2007
    Applicant: OKI ELECTRIC INDUSTRY CO., LTD.
    Inventors: Katsuaki Kaifu, Juro Mita
  • Publication number: 20060214187
    Abstract: A wafer for semiconductor device fabrication, from which large output power can be obtained by making the off-state breakdown voltage higher than in the prior art. The wafer for semiconductor device fabrication comprises a substrate, GaN electron transit layer formed on the side of the principal surface of the substrate, and AlGaN electron supply layer formed on the electron transit layer. The thickness of the electron transit layer is from 0.2 to 0.9 ?m.
    Type: Application
    Filed: March 20, 2006
    Publication date: September 28, 2006
    Applicant: Oki Electric Industry Co., Ltd.
    Inventors: Juro Mita, Hideyuki Okita, Fumihiko Toda
  • Patent number: 6624255
    Abstract: A polymer material containing a repetitive unit having a formula: The polymer material has a higher glass transition temperature and a lower water absorption than those of deuterated PMMA, but has a transparency equivalent with that of deuterated PMMA. The material also shows neither light absorption nor scattering in an operating wavelength region.
    Type: Grant
    Filed: September 18, 2001
    Date of Patent: September 23, 2003
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Takeshi Koyano, Yoshinori Maeno, Juro Mita, Katsuaki Kaifu
  • Patent number: 6528172
    Abstract: The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and an organometallic compound obtainable by hydrolyzing composite metal alkoxides, formed by any two or more of said metal alkoxides, with water alone or in combination with a catalyst, and contains Bi in a molar amount 1-1.1 times as great as the stoichiometric amount; a ferroelectric thin film (5), a ferroelectric capacitor (10) and a ferroelectric memory with the use of such a coating solution; and a method for producing the same.
    Type: Grant
    Filed: December 27, 2000
    Date of Patent: March 4, 2003
    Assignees: Tokyo Ohka Kogyo Co., Ltd., Oki Electric Industry Co., Ltd.
    Inventors: Yoshihiro Sawada, Akira Hashimoto, Ichiro Koiwa, Juro Mita, Yukihisa Okada, Takao Kanehara, Hiroyo Kato
  • Patent number: 6403160
    Abstract: An object of the present invention is to reduce a leakage current of a Pb Zr Ti O base ferroelectric thin film when a voltage is applied. A ferroelectric thin film comprising a composition of PbZrxTi1−xSbyO3 (where 0 <x<1, 0.0001≦y≦0.05) is provided herein as well as a method of producing it. The presence of the Sb serves to reduce the leakage current of the film when a voltage is applied.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: June 11, 2002
    Assignees: Oki Electric Industry Co., Ltd., Tokyo Ohka Kogyo, Co., Ltd.
    Inventors: Ichiro Koiwa, Juro Mita, Takao Kanehara, Akira Hashimoto, Yoshihiro Sawada
  • Patent number: 6372411
    Abstract: A polymer pattern forming method including the steps of (a) generating radicals in a pattern forming region of a matrix layer which uniformly contains a radical generating agent, thereby forming a patterned latent image due to the radicals in the pattern forming region; and (b) bringing a monomer which polymerizes by radical polymerization into contact with the matrix layer in which the patterned latent image has been or is being formed, to have the radicals which have been or are being generated induce a chain addition polymerization of the monomer so as to form a polymer pattern on the pattern forming region.
    Type: Grant
    Filed: February 24, 1999
    Date of Patent: April 16, 2002
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Takeshi Koyano, Yoshinori Maeno, Juro Mita, Katsuaki Kaifu
  • Publication number: 20020021883
    Abstract: An optical waveguide having a clad and a core, the core being made of polymer material containing a repetitive unit having formula (1), (2) or (3): 1
    Type: Application
    Filed: September 18, 2001
    Publication date: February 21, 2002
    Inventors: Takeshi Koyano, Yoshinori Maeno, Juro Mita, Katsuaki Kaifu
  • Patent number: 6327415
    Abstract: An optical waveguide having a clad and a core, the core being made of polymer material containing a repetitive unit having formula (1), (2) or (3): Each of these polymer materials has a higher glass transition temperature and lower water absorption than those of deuterated PMMA, has a transparency equivalent with that of deuterated PMMA, and shows neither light absorption nor scattering in the operating wavelength region. An optical waveguide with a core fabricated using these polymer materials is high in heat resistance and low in water absorption. Thus using the waveguide will successfully provide optical communication elements with an advanced durability against the environment.
    Type: Grant
    Filed: March 20, 2000
    Date of Patent: December 4, 2001
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Takeshi Koyano, Yoshinori Maeno, Juro Mita, Katsuaki Kaifu
  • Patent number: 6303231
    Abstract: The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi. Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and contains composite metal alkoxides formed by any two or more of said metal alkoxides; and a ferroelectric thin film, a ferroelectric capacitor and a ferroelectric memory formed by the use of such coating solution, and a method for producing the same.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: October 16, 2001
    Assignees: Tokyo Ohka Kogyo Co., Ltd., Oki Electric Industry Co., Ltd.
    Inventors: Yoshihiro Sawada, Akira Hashimoto, Tetsuya Osaka, Ichiro Koiwa, Juro Mita, Yoshinori Maeno, Yukihisa Okada, Hiroyo Kato
  • Publication number: 20010010867
    Abstract: The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and an organometallic compound obtainable by hydrolyzing composite metal alkoxides, formed by any two or more of said metal alkoxides, with water alone or in combination with a catalyst, and contains Bi in a molar amount 1-1.1 times as great as the stoichiometric amount; a ferroelectric thin film (5), a ferroelectric capacitor (10) and a ferroelectric memory with the use of such a coating solution; and a method for producing the same.
    Type: Application
    Filed: December 27, 2000
    Publication date: August 2, 2001
    Inventors: Yoshihiro Sawada, Akira Hashimoto, Ichiro Koiwa, Juro Mita, Yukihisa Okada, Takao Kanehara, Hiroyo Kato
  • Patent number: 6197102
    Abstract: The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi, Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and an organometallic compound obtainable by hydrolyzing composite metal alkoxides, formed by any two or more of said metal alkoxides, with water alone or in combination with a catalyst, and contains Bi in a molar amount 1-1.1 times as great as the stoichiometric amount; a ferroelectric thin film (5), a ferroelectric capacitor (10) and a ferroelectric memory with the use of such a coating solution; and a method for producing the same.
    Type: Grant
    Filed: January 15, 1998
    Date of Patent: March 6, 2001
    Assignees: Tokyo Ohka Kogyo Co., Ltd., Oki Electric Industry Co., Ltd.
    Inventors: Yoshihiro Sawada, Akira Hashimoto, Ichiro Koiwa, Juro Mita, Yukihisa Okada, Takao Kanehara, Hiroyo Kato
  • Patent number: 6120912
    Abstract: The invention discloses a coating solution for use in forming Bi-based ferroelectric thin films containing Bi, metallic element A (at least one selected from the group consisting of Bi. Pb, Ba, Sr, Ca, Na, K and rare earth elements) and metallic element B (at least one selected from the group consisting of Ti, Nb, Ta, W, Mo, Fe, Co and Cr), wherein it contains metal alkoxides of Bi, metallic element A and metallic element B respectively, and contains composite metal alkoxides formed by any two or more of said metal alkoxides; and a ferroelectric thin film, a ferroelectric capacitor and a ferroelectric memory formed by the use of such coating solution, and a method for producing the same.
    Type: Grant
    Filed: June 22, 1998
    Date of Patent: September 19, 2000
    Assignees: Tokyo Ohka Kogyo Co., Ltd., Oki Electric Industry Co., Ltd.
    Inventors: Yoshihiro Sawada, Akira Hashimoto, Tetsuya Osaka, Ichiro Koiwa, Juro Mita, Yoshinori Maeno, Yukihisa Okada, Hiroyo Kato
  • Patent number: 6025979
    Abstract: A magnetoresistive sensor has a magnetic bias field source that generates an alternating magnetic bias field, a giant magnetoresistive sensing element positioned in the alternating magnetic bias field, and a resistance detecting circuit that detects changes in the electrical resistance of the giant magnetoresistive sensing element caused by the combined action of the alternating magnetic bias field and an external magnetic field. The alternating magnetic bias field enables small external magnetic fields to be detected with high sensitivity.
    Type: Grant
    Filed: September 1, 1998
    Date of Patent: February 15, 2000
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Haruki Yamane, Juro Mita