Thick Insulator Portion Patents (Class 257/395)
  • Patent number: 5548147
    Abstract: A high voltage PMOS or NMOS transistor 7 has improved on-resistance by truncating gate field oxide 43 so that drain region 42 may be implanted closer to channel region 49 than possible otherwise. By shortening the physical distance d2 between drain 42 and channel region 49, the drain to source on-resistance of the high voltage device is reduced and the performance of high voltage device 7 is thereby improved.
    Type: Grant
    Filed: January 5, 1995
    Date of Patent: August 20, 1996
    Assignee: Texas Instruments Incorporated
    Inventor: Chia-Cu P. Mei
  • Patent number: 5521407
    Abstract: The first element separation oxide film consisting of a plurality of line-shaped portions parallel to the bit line is formed on the surface of the P-type silicon substrate. The first and second trenches are formed in that portion of the P-type silicon substrate which is located between an adjacent pair of line-shaped portions of the first element separation oxide film such that both sides of the trenches come in contact with the first element separation oxide film. A sheath plate capacitor is formed in each of the trenches. The second element separation oxide film having a thickness less than that of the first element separation oxide film is formed on that portion of the surface of the P-type silicon substrate which is located between the first and second trenches.
    Type: Grant
    Filed: November 3, 1994
    Date of Patent: May 28, 1996
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yusuke Kohyama, Akira Sudo
  • Patent number: 5510648
    Abstract: An insulated gate semiconductor device (10) having a pseudo-stepped channel region (20B) between two P-N junctions (21B and 22B). The pseudo-stepped channel region (20B) is comprised of an enhancement mode portion (26B) and a depletion mode portion (28B), the enhancement mode portion (26B) being more heavily doped than the depletion mode portion (28B). One P-N junction (21B) is formed at an interface between a source region (18B) and the enhancement mode portion (26B). The enhancement mode portion (26B) has a substantially constant doping profile, thus slight variations in the placement of the source region (18B) within the enhancement region (26B) do not result in significant variations in the threshold voltage of the insulated gate semiconductor device (10). The insulated gate semiconductor device (10) is well suited for the design of low voltage circuits because of the small variations of the threshold voltage.
    Type: Grant
    Filed: September 7, 1994
    Date of Patent: April 23, 1996
    Assignee: Motorola, Inc.
    Inventors: Robert B. Davies, Peter J. Zdebel, Juan Buxo
  • Patent number: 5448081
    Abstract: A MOSFET device (100) having a silicon carbide substrate (102). A channel region (106) of a first conductivity type and an epitaxial layer (104) of a second conductivity type are located above the silicon carbide substrate (102). First and second source/drain regions (118), also of the first conductivity type are located directly within the channel region (106). No well region is placed between the first and second source/drain regions (118) and the channel region (106). A gate (120) is separated from the channel region (106) by an insulator layer (110). Insulator layer (110) has a thin portion (114) and a thick portion (116).
    Type: Grant
    Filed: February 22, 1993
    Date of Patent: September 5, 1995
    Assignee: Texas Instruments Incorporated
    Inventor: Satwinder Malhi
  • Patent number: 5382820
    Abstract: A method of fabrication of an semiconductor device comprises applying an impurity of a predetermined polarity to a silicon substrate; forming a well by applying an impurity of an opposite polarity to a region in the silicon substrate; forming a first masking layer on the surface of the substrate; providing openings in the masking layer and implanting dopant ions of a first polarity into the surface of the substrate in a set of first regions selected in the substrate and the well forming a second masking layer on the surface of the substrate; implanting dopant ions of a second polarity through a second mask in other regions selected in the well and the substrate; removal of the second masking layer; formation of field oxide structures over the first and second regions; forming gate oxide layers above the exposed portions of the first and second central regions; and formation of conductive gate structures over the gate oxide layers.
    Type: Grant
    Filed: December 8, 1993
    Date of Patent: January 17, 1995
    Assignee: United Microelectronics Corporation
    Inventors: Sheng-Hsing Yang, Nai-Jen Yeh
  • Patent number: 5353245
    Abstract: An integrated circuit, illustratively an SRAM, with pull down gates symmetrically positioned with respect to the ground line is disclosed. The symmetric positioning helps to insure cell stability.
    Type: Grant
    Filed: August 24, 1993
    Date of Patent: October 4, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Kuo-Hua Lee, Janmye Sung
  • Patent number: 5331181
    Abstract: A non-volatile semiconductor memory providing a semiconductor substrate including source and drain diffusion regions and a gate electrode, and an insulating film which is at least provided on the semiconductor substrate just below the gate electrode and has a smaller dielectric breakdown strength on the source side than on the drain side, wherein the insulating film is comprised of a laminated film having a multilayer structure on the drain side and a single-layer film or multilayer film which is broken down at a smaller voltage on the source side than on the drain side, and a predetermined voltage is applied to break down the single-layer film or multilayer film on the source side, so that data can electrically be written only once.
    Type: Grant
    Filed: June 25, 1993
    Date of Patent: July 19, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kenichi Tanaka, Yoshimitsu Yamauchi, Keizo Sakiyama
  • Patent number: 5323044
    Abstract: A bi-directional switch includes a well region of a first conductivity type placed within a substrate. A first region of second conductivity type is placed within the well. A second contact region of second conductivity type is placed within the well. A drift region of second conductivity is placed between the first contact and the second contact. The drift region is separated from the first contact by a first channel region and is separated from the second contact by a second channel region. A first gate region is placed over the first channel region and a second gate region over the second channel region.
    Type: Grant
    Filed: October 2, 1992
    Date of Patent: June 21, 1994
    Assignee: Power Integrations, Inc.
    Inventors: Vladimir Rumennik, Wayne B. Grabowski
  • Patent number: 5270566
    Abstract: A MOS device comprising a parallel array of a plurality of unit structures on a substrate, each unit structure including a first semiconductor layer of a first conductivity type, an oxide layer disposed on a major surface of the first semiconductor layer, a control electrode formed on the oxide layer, and second and third semiconductor layers separated from each other by the first semiconductor layer. The electric current flowing through a surface layer in contact with the oxide layer is controlled by the voltage applied to the control electrode, and the oxide layer is relatively thick between the first semiconductor layer and the control electrode on the periphery of the unit structures located on the periphery of the substrate and relatively thin between the first semiconductor layer and control electrode in other regions of the MOS device.
    Type: Grant
    Filed: December 10, 1992
    Date of Patent: December 14, 1993
    Assignee: Fuji Electric Co., Ltd.
    Inventor: Tatsuhiko Fujihara
  • Patent number: 5247200
    Abstract: A BiMOS integrated circuit device comprises a bipolar transistor and at least one MOSFET. The collector and emitter of the bipolar transistor are connected to a high potential source and a low potential source, respectively. The MOSFET has two gate electrodes, a source, and a drain. The source is connected to the high potential source, and the drain is the base of the bipolar transistor by a diffusion layer. The diffusion layer is located between the gate electrodes, and serves as both the base of the bipolar transistor and the drain of the MOSFET. Therefore, the MOSFET has a great channel width, and a large current can be supplied to the base of the bipolar transistor. In other words, the MOSFET has a great driving capability, and the bipolar transistor has a high amplification factor.
    Type: Grant
    Filed: September 23, 1991
    Date of Patent: September 21, 1993
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Hiroshi Momose, Kouji Makita
  • Patent number: 5198683
    Abstract: A memory cell layout achieves a reduced cell area. In one embodiment, a six transitor (6T) SRAM cell has two vertical thin-film transistors (18 and 20) as load transistors, two transfer transistors (10 and 12), two latch transistors (14 and 16), and two storage nodes. NODE 1 and NODE 2 of the cell each have a minimum feature defined by trenches (60). Four of five interconnects associated with each node are located within the respective trench. For example in NODE 1, a drain of latch transistor (14), a gate of latch transistor (16), a drain of load transistor (18), and a current electrode of transfer transistor (10) are electrically coupled within or beneath one trench (60). A remaining interconnection of NODE 1, a gate of load transistor 20, is located within the trench associated with NODE 2. Thus, ten interconnects of the memory cell are contained within areas defined by two minimum features.
    Type: Grant
    Filed: May 3, 1991
    Date of Patent: March 30, 1993
    Assignee: Motorola, Inc.
    Inventor: Richard D. Sivan
  • Patent number: 5166763
    Abstract: A static type semiconductor memory device includes memory cells each including a pair of field effect transistors (FETs) each having a gate electrode cross-coupled to a drain region connected to a power source terminal by way of a load register. The memory device includes a semiconductor substrate of a first conductivity type, polycrystal silicon layers containing impurities of a second conductivity type and first and second FETs. The polycrystal silicon layers are formed with a spacing from one another for defining a channel region on the substrate. The first and second FETs are formed on the substrate and each includes source and drain regions of a second conductivity type and a gate electrode. The source and drain regions are formed below the polycrystal silicon layers by introducing impurities from the polycrystal silicon layers into the substrate. The gate electrode is formed on the channel region and the polycrystal silicon layers with a gate insulating film interposed.
    Type: Grant
    Filed: April 30, 1991
    Date of Patent: November 24, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tomohisa Wada, Masahide Inuishi
  • Patent number: 5164806
    Abstract: An element isolating structure employed for isolating the elements of a semiconductor substrate has an impurity region having a concentration lower than that of a source/drain and a channel stop region, between the source/drain of an MOS transistor formed in an active region, and the channel stop region formed under an LOCOS film.A field shield isolating structure has a low concentrated impurity region between the source/drain of an MOS transistor formed in the active region and the substrate surface region covered by a field shield electrode layer. The low concentrated impurity region improves its junction breakdown voltage in the boundary region with the element isolating region.An improved LOCOS film is formed into an amorphous region on the surface of the substrate by an oblique rotating ion implanting method, and the amorphous region is formed by thermal oxidation. The method suppresses the emergence of a bird's beak.
    Type: Grant
    Filed: May 13, 1991
    Date of Patent: November 17, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masao Nagatomo, Hiroki Shimano, Tomonori Okudaira, Yoshinori Okumura