With Pn Junction Isolation Patents (Class 257/544)
  • Patent number: 5394007
    Abstract: A junction isolated P-well is formed for high performance BiCMOS. Two dopants of opposite conductivity types are implanted and co-diffused inside an annular N-type region to form a narrow N-type buried layer positioned between two P-type regions. N-type buried layer is formed having P-type doped regions above and below the N-type buried layer so that the N-type buried layer is narrow. The P-type region above the N-type buried layer provides for a retrograde profile of the P-well formed above it. Besides the P-well isolation, the P-type region below the N-type buried layer acts as a ground plane which collects noise, which helps to prevent it from being coupled to other devices of the BiCMOS circuit.
    Type: Grant
    Filed: September 13, 1993
    Date of Patent: February 28, 1995
    Assignee: Motorola, Inc.
    Inventors: Robert H. Reuss, David J. Monk, Christopher P. Dragon
  • Patent number: 5386135
    Abstract: Disclosed is a semiconductor device, such as a semiconductor memory device, having structure wherein invasion of minority carriers from the semiconductor substrate into components of the device, formed on the substrate, can be avoided. The semiconductor memory device can be an SRAM or DRAM, for example, and includes a memory array and peripheral circuit on a substrate. In one aspect of the present invention, a buried layer of the same conductivity type as that of the substrate, but with a higher impurity concentration than that of the substrate, is provided beneath at least one of the peripheral circuit and memory array. A further region can extend from the buried layer, for example, to the surface of the semiconductor substrate, the buried layer and further region in combination acting as a shield to prevent minority carriers from penetrating to the device elements.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: January 31, 1995
    Assignee: Hitachi, Ltd.
    Inventors: Shinji Nakazato, Hideaki Uchida, Yoshikazu Saito, Masahiro Yamamura, Yutaka Kobayashi, Takahide Ikeda, Ryoichi Hori, Goro Kitsukawa, Kiyoo Itoh, Nobuo Tanba, Takao Watanabe, Katsuhiro Shimohigashi, Noriyuki Homma
  • Patent number: 5384482
    Abstract: An input protective circuit provided between a semiconductor integrated circuit and an input bonding pad formed on a semiconductor substrate includes an N or P type electric field intensity relaxing region for setting a clamp level of the input protective circuit. The electric field intensity relaxing region is formed between an N.sup.+ -type semiconductor region connected to an input wiring layer and a P.sup.+ -type semiconductor region connected to a reference potential wiring layer.
    Type: Grant
    Filed: May 18, 1993
    Date of Patent: January 24, 1995
    Assignee: NEC Corporation
    Inventor: Yasutaka Nakashiba
  • Patent number: 5382824
    Abstract: An integrated circuit includes a photo diode having a first electrically isolated portion of an epitaxial layer of a first conductivity type, a first semiconductor layer of a second conductivity type disposed therein, a second semiconductor layer of the first conductivity type disposed in the first semiconductor layer, and a third semiconductor layer of the second conductivity type disposed in the second semiconductor layer.
    Type: Grant
    Filed: July 13, 1993
    Date of Patent: January 17, 1995
    Assignee: Landis & Gyr Business Support AG
    Inventor: Radivoje Popovic
  • Patent number: 5349231
    Abstract: A method and apparatus are provided for bidirectional current conduction between first and second nodes of an electronic circuit. A first substantially constant current is conducted through a first current mirror pair of transistors coupled between the first and second nodes, in a first direction away from the first node toward the second node, in response to the first node having a voltage higher than the second node. A second substantially constant current is conducted through a second current mirror pair of transistors coupled between the first and second nodes, in a second direction away from the second node toward the first node, in response to the first node having a voltage lower than the second node.
    Type: Grant
    Filed: June 18, 1993
    Date of Patent: September 20, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Fernando D. Carvajal
  • Patent number: 5338963
    Abstract: Soft error immunity of a storage cell is greatly increased by division of a storage node into at least two portions and location of those portions on opposite sides of an isolation structure, such as a well of a conductivity type opposite to that of the substrate in which transistors of the memory cell may also be formed. The isolation structure thus limits collection of charge to only one of the portions of the storage node and reduces charge collection efficiency to a level where a critical amount of charge cannot be collected in all but a statistically negligible number of cases when such charge is engendered by impingement by ionizing radiation, such as energetic alpha particles. The layout of the memory cell having this feature also advantageously provides a simplified topology for the formation of additional ports comprising word line access transistors and bit lines.
    Type: Grant
    Filed: April 5, 1993
    Date of Patent: August 16, 1994
    Assignee: International Business Machines Corporation
    Inventors: William A. Klaasen, Wen-Yuan Wang
  • Patent number: 5321291
    Abstract: A power MOSFET device formed in a face of a semiconductor layer of a first conductivity type is provided. A first, second and third source region of a second conductivity type are formed in the face of the semiconductor layer within a moat and adjacent to its edges. A source conductor is insulatively disposed adjacent the face of the semiconductor layer and contacts the first, second and third source regions at a plurality of locations. A first and second drain region of a second conductivity type is also formed in the face of the semiconductor layer disposed spaced from and between the first and second source regions and the second and third source regions, respectively. A drain conductor is insulatively disposed adjacent the face of the semiconductor layer and contacts the first and second drain regions at a plurality of locations.
    Type: Grant
    Filed: May 26, 1993
    Date of Patent: June 14, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Donald J. Redwine
  • Patent number: 5313086
    Abstract: A semiconductor device includes a P-type semiconductor substrate, an N-type well region formed on the surface of the substrate, a P-type well region formed in the N-type well region and a MOSFET as a flash memory element formed in the P-type well region. Upon erasure of the information in the flash memory, a high voltage is temporarily charged to the P-type and N-type well regions, in such a manner that a first high voltage pulse of a predetermined width is charged to the N-type well region, a second high voltage pulse having a pulse width narrower than the pulse width of the first pulse is charged to the P-type well region in a period between the initiation end and the termination end of the first pulse.
    Type: Grant
    Filed: August 25, 1992
    Date of Patent: May 17, 1994
    Assignee: NEC Corporation
    Inventor: Toshikatsu Jinbo
  • Patent number: 5311462
    Abstract: A method is described for locating content addressable memory (CAM) bit cells on a column within a main memory array and within the guard ring surrounding the main memory array.
    Type: Grant
    Filed: December 19, 1991
    Date of Patent: May 10, 1994
    Assignee: Intel Corporation
    Inventor: Steven Wells
  • Patent number: 5293060
    Abstract: A semiconductor device has an upper well of a first conductivity type formed from the surface of an active region separated by an isolation oxide film at the surface of a semiconductor substrate to a predetermined depth. A first conductivity type layer of high concentration is formed along the entire region of an active region to enclose the bottom of the upper well of the first conductivity type. A lower well of the first conductivity type of a predetermined thickness is formed as a buried layer to enclose the bottom of the first conductivity type layer of high concentration. According to this structure, the spreadout of impurities into the active region due to diffusion at the time of thermal treatment is suppressed.
    Type: Grant
    Filed: July 6, 1992
    Date of Patent: March 8, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeki Komori, Katsuhiro Tsukamoto
  • Patent number: 5283460
    Abstract: An optical semiconductor includes a photo diode integrated with a transistor built on first and second epitaxial layers grown on a substrate, the first epitaxial layer is grown on the substrate from intrinsic material. The second epitaxial layer is grown doped on the first epitaxial layer. A separating area divides the optical semiconductor into first and second isolated islands. The separating area is made up of a lower separating area, a middle separating area and an upper separating area united to form a single separating area. The lower separating area is diffused at least upward from an interface between the substrate and the first epitaxial area. The middle separating area is diffused both downward and upward from an interface between the first and second epitaxial layers. The upper separating area is diffused downward from the surface of the second epitaxial layer. The photo diode is formed in the first island area, and the transistor is formed in the second island area.
    Type: Grant
    Filed: February 12, 1992
    Date of Patent: February 1, 1994
    Assignee: Sanyo Electric Co., Ltd.
    Inventor: Keizi Mita
  • Patent number: 5264716
    Abstract: A high density substrate plate DRAM cell memory device is described in which a buried plate region is formed adjacent to deep trench capacitors such that the substrate region of DRAM transfer FETs can be electrically isolated from other FETs on a semiconductor substrate. The buried region is partially formed by lateral outdiffusion from the sidewalls of the deep trenches and partially formed by an N-well surface diffusion which entirely surrounds the DRAM array region.
    Type: Grant
    Filed: January 9, 1992
    Date of Patent: November 23, 1993
    Assignee: International Business Machines Corporation
    Inventor: Donald M. Kenney
  • Patent number: 5220190
    Abstract: A semiconductor device according to the present invention has a semiconductor body of a first conductivity type, three islands of a second conductivity type, formed in the surface of the semiconductor body. Two wells of the first conductivity are formed in the first and second islands. The device further has a charge transfer device which back gate is formed of the first well, an insulated-gate FET of the first conductivity type which back gate is formed of the second island, an insulated-gate FET of the second conductivity type which back gate is formed of the second well, and a bipolar transistor which collector is formed of the third island. The first island surrounds the first well which serves as back gate of the charge transfer device, and blocks the noise generated in the first well. Hence, the other islands are free from the influence of the noise.
    Type: Grant
    Filed: January 16, 1991
    Date of Patent: June 15, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Minoru Taguchi, Kazuo Kihara
  • Patent number: 5181091
    Abstract: A battery-backed integrated circuit, with a double diode structure connected to signal lines. In the double diode structure, a first junction is three-dimensionally enclosed by a second junction, so that minority carriers generated at the first junction will be collected at the second junction. Thus, when a negative transient voltage appears on the signal line, the first junction can be forward biassed to source the needed current from ground, with minimal minority carrier injection.
    Type: Grant
    Filed: September 16, 1991
    Date of Patent: January 19, 1993
    Assignee: Dallas Semiconductor Corp.
    Inventors: Thomas E. Harrington, III, Robert D. Lee