Patents Assigned to Nippon Steel Semiconductor Corporation
  • Patent number: 5973980
    Abstract: An on-chip voltage regulator for controlling a gate of a regulator transistor having a first terminal coupled to receive an external power supply voltage and a second terminal coupled to provide a regulated voltage level to an internal circuit formed on a chip on which the on-chip voltage regulator is formed. The on-chip voltage regulator includes circuitry for detecting when a high current load to which the second terminal of the regulator transistor is coupled is activated. A control transistor is provided having a first terminal coupled to receive the external power supply voltage, a second terminal coupled to the gate of the regulator transistor, and a gate responsive to the means for detecting. In operation, a control voltage with an overshoot portion having preselected duration is generated on the gate of the regulator transistor in response to the activation of the high current load.
    Type: Grant
    Filed: July 23, 1998
    Date of Patent: October 26, 1999
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: John William Tiede, Jon Allan Faue
  • Patent number: 5917230
    Abstract: An integrated circuit having a voltage source and a plurality of conductive power bus tiers extending across the integrated circuit. Each of the power bus tiers are electrically coupled in parallel to the voltage source. The integrated circuit includes a filter capacitor having a first plate and a second plate that are separated by a capacitor dielectric. The first plate forms a bus strap coupling to each of the plurality of power bus tiers.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: June 29, 1999
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventor: Larry L. Aldrich
  • Patent number: 5900021
    Abstract: A configurable input device for an integrated circuit having a plurality of input pads, the input device including a plurality of buffers, where each buffer is associated with one of the input pads. Each buffer receives a mode select signal and the buffer is responsive to the mode select signal to place the buffer in an enabled mode or a disabled mode. A receiver portion within each buffer is coupled to the associated input pad. The receiver portion pulls the associated input pad to a preselected logic state while the buffer is in the disabled mode. An output driver within each buffer generates an output signal responsive to a signal on the associated input pad while the buffer is in the enable mode and provides a high impedance while the buffer is in the disabled mode. An output node is coupled to the output drivers of the plurality of buffers.
    Type: Grant
    Filed: April 4, 1997
    Date of Patent: May 4, 1999
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: John William Tiede, Jon Allan Faue
  • Patent number: 5869376
    Abstract: The present invention has the object of offering a semiconductor production method which simplifies the fabrication of gate electrodes for MOS-type semiconductor elements and allows a high yield to be maintained. For this purpose, it has steps of forming a field-shield gate insulation film on a semiconductor substrate, forming polycrystalline silicon films having an etching rate which is greater at an upper side than a lower side thereon, and etching the polycrystalline silicon films under conditions which allow for side etching with the silicon oxide film as a mask, so as to make gradually tapered inclines on side walls of field-shield gate electrode.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: February 9, 1999
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Yugo Tomioka
  • Patent number: 5859466
    Abstract: An LSI semiconductor device having a device isolation structure and a method of fabricating the isolation structure are presented. The device is a buried-type field-shielding device which is fabricated in non-active regions of the LSI circuit, and includes field-shield insulator film formed on the interior walls of trench cavities formed on the substrate and the field-shield electrodes buried within the trench cavity. Unlike the conventional buried-type isolation devices, the top surface of present isolation structure is level with the upper surface of the substrate. Therefore, this device structure utilizes the interior space of the substrate rather than the surface area of the substrate as in the conventional field-shield isolation structure.
    Type: Grant
    Filed: June 6, 1996
    Date of Patent: January 12, 1999
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Toshio Wada
  • Patent number: 5851873
    Abstract: A semiconductor memory device has a long refresh time and offers high reliability by minimizing junction leakage current, resulting in increased charge retention time. This is achieved by optimizing the diffusion layer junction depth formed in a deeper region of the semiconductor substrate which is in electrical contact with the impurity diffusion layer. Typically, junction depth is in excess of 0.1 .mu.m. Two methods for achieving such a structure are also provided. In one method, implantation voltage in excess of 80 KeV is used to implant P ions to form a high carrier concentration profile at a junction depth of greater than 0.1 .mu.m. In another method, implantation process are carried out in two steps so as to force the previously implanted ions deeper into the storage node electrode, and a subsequent heat treatment is carried out to further distribute the dopant ions into the substrate of the semiconductor substrate so as to disperse crystal defects into the substrate.
    Type: Grant
    Filed: October 22, 1996
    Date of Patent: December 22, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventors: Ichiro Murai, Hidemi Arakawa, Shinobu Shigeta
  • Patent number: 5821165
    Abstract: The present invention provides a method of fabrication for semiconductor devices which enables a photolithography technique in a fabrication process to have a maximal effect on the transistor characteristics. Polysilicon film 16 and silicon nitride film 17 are formed to active transistor 11 and field shield isolation transistor 12, with isotropic etching of silicon nitride film 17 carried out using a resist pattern 20 which was patterned within the minimum processing width as the mask. Then, using the pattern of silicon nitride film 17 as a mask, thermal oxidation of polysilicon film 16 is carried out. Next, after eliminating silicon nitride film 17, anisotropic etching of polysilicon film 16 is carried out using silicon oxide film 21 as a mask, silicon oxide film 21 being formed by thermal oxidation of polysilicon film 16. In this way, a contact pad 22 formed of polysilicon film 16 is completed.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: October 13, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Teruo Asami
  • Patent number: 5789778
    Abstract: A gate electrode comprises a conductive gate electrode body and gate side walls. The channel region beneath the gate electrode has an NUDC structure having a p.sup.- impurity region and p.sup.+ impurity regions. The p.sup.- impurity region is formed before the gate electrode body. After the formation of the gate electrode body, the p.sup.+ impurity regions are formed by ion implantation before the gate side walls. The ion implantation is carried out perpendicular to the substrate so that the implanted ions will not reach further around the center of the channel region. Of the gate oxide films over the channel region, the thickness of the gate oxide films at both ends of the channel region is thinner than that of the gate oxide film in the middle of the channel length so as to suppress lowering of the current drivability.
    Type: Grant
    Filed: October 7, 1996
    Date of Patent: August 4, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Ichiro Murai
  • Patent number: 5763298
    Abstract: An integrated circuit having a first and second bond pads, a latch circuit, and a voltage lead. Different configurations of the internal circuitry of the integrated circuit are selected by applying the voltage lead either to the first or second bond pads. This result is achieved because the latch circuit, coupled between the first and second bond pads, is capable of inverting the voltage response seen at the first bond pad.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: June 9, 1998
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: Michael Parris, Michael V. Cordoba
  • Patent number: 5760441
    Abstract: A p-type high concentration doped region is formed in a p-type semiconductor substrate between a n-type doped region as part of an input protection circuit and another n-type doped region as part of internal circuitry. A plate is divided into two over the high concentration doped region. The high concentration doped region suppresses generation of a parasitic MOS transistor with the plate for a gate, one of the n-type doped regions for a source, and the other for a drain.
    Type: Grant
    Filed: October 25, 1996
    Date of Patent: June 2, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Eiichi Iwanami
  • Patent number: 5754464
    Abstract: A mask ROM with increased memory capacity is disclosed. Besides MOS transistors each comprising a memory cell, MOS field shield transistors for device isolation, originally provided for electrically isolating the memory cell transistors, are also used as additional memory cells in addition to providing their isolating function. To write data in one of the field shield transistor, the threshold voltage of the field shield transistor is lowered, compared to field shield transistors in other regions. This is done by ion implantation of an n-type impurity into a p-type silicon substrate in a region beneath a gate electrode of the field shield transistor (a channel region). Data is read by judging on/off of the transistors when an intermediate voltage, between a high threshold voltage and a low threshold voltage is applied to a field shield line.
    Type: Grant
    Filed: December 13, 1996
    Date of Patent: May 19, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Yugo Tomioka
  • Patent number: 5717643
    Abstract: Four I/O pads are allocated to a group from one end to the other. A test circuit is provided for each of the groups. The four I/O pads are only connected to a test data terminal of an IC tester while the rest of the I/O pads are not connected. The test circuit comprises: a test mode detection circuit for detecting the device shifting to the test mode; a test mode writing circuit for writing data inputted from one of the I/O pads into four memory cells; a coincidence circuit for determining whether the data read from the four memory cells coincide with each other; and a data output circuit for outputting the result to the I/O pad.
    Type: Grant
    Filed: September 19, 1996
    Date of Patent: February 10, 1998
    Assignee: Nippon Steel Semiconductor Corporation
    Inventors: Eiichi Iwanami, Toshio Wada
  • Patent number: 5680362
    Abstract: A circuit and method for concurrently addressing at least two rows of memory cells of a memory array of a memory device. By concurrently addressing at least two rows of memory cells during testing of the memory device during a burn-in period, the memory device can be tested in a reduced time period.
    Type: Grant
    Filed: May 30, 1996
    Date of Patent: October 21, 1997
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: Michael C. Parris, Douglas B. Butler, Kim C. Hardee
  • Patent number: 5671392
    Abstract: A circuit and method for a memory device, such as a synchronous dynamic random access memory (SDRAM) having at least two memory banks. Columns of at least two memory banks are concurrently addressable to permit data to be written to, or read from, the at least two memory banks concurrently. By writing data concurrently to more than one memory bank, testing of the memory of the memory device can be effectuated in a reduced period of time. Data can also be written or read from a single bank in a multi-bank RAM without requiring that a particular bank be specified during a read/write command.
    Type: Grant
    Filed: April 11, 1995
    Date of Patent: September 23, 1997
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: Michael Parris, H. Kent Stalnaker
  • Patent number: 5668027
    Abstract: A MOS transistor semiconductor device has a gate electrode portion with a spacer film, diffused regions diffused with dopants, and element-separating regions. After the formation of the gate on the substrate, a spacer oxide is formed adjacent to the gate. A polysilicon layer doped with the same dopants as the diffused regions is formed between the element-separating regions and the spacer film. The polysilicon layer is overlaps portions of the gate electrode and the element-separating regions that are close to the diffused regions. Thermal diffusion of the dopants from the polysilicon layer to the substrate is performed to further dope the diffused regions. After an insulation layer is formed over the polysilicon layer, connection holes are formed through the insulation layer to connect the polysilicon layer to metal interconnects. In this MOS transistor, the polysilicon layer provides holes that are larger in diameter than holes at the openings of the diffused regions that are part of the substrate surface.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: September 16, 1997
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Masayuki Hashimoto
  • Patent number: 5663915
    Abstract: An improved current sensing differential amplifier which includes a separate p-channel bias stage to reduce the minimum operating voltage VCC of the circuit. The separate p-channel bias stage is also used to pre-bias a driver stage to more quickly generate differential output currents. Finally, the improved current sensing differential amplifier also includes negative feedback transistors to improve the recovery time of the circuit.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: September 2, 1997
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventor: Kenneth J. Mobley
  • Patent number: 5644545
    Abstract: A method and apparatus for compensating for weak elements of a dynamic memory circuit on an integrated circuit chip is disclosed. The method includes identifying weak elements in the memory circuit. The elements may be identified by a known test program, and may be bits, blocks, or other portion of a dynamic memory circuit. The locations of the identified weak elements are programmed into a programmable memory, and the programmed information in the programmable memory is used to refresh the identified weak elements at a different rate from the refresh rate of other bits. This allows an extended or longer refresh interval to be used for the strong elements, while providing adequate refresh for the weak elements, thereby reducing the refresh interval required for the overall memory circuit from the refresh interval which normally would have been used.
    Type: Grant
    Filed: February 14, 1996
    Date of Patent: July 1, 1997
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventor: David E. Fisch
  • Patent number: 5641697
    Abstract: A p-type high concentration doped region is formed in a p-type semiconductor substrate between a n-type doped region as part of an input protection circuit and another n-type doped region as part of internal circuitry. A plate is divided into two over the high concentration doped region. The high concentration doped region suppresses generation of a parasitic MOS transistor with the plate for a gate, one of the n-type doped regions for a source, and the other for a drain.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: June 24, 1997
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Eiichi Iwanami
  • Patent number: 5557135
    Abstract: To electrically isolate a MOSFET formed on a substrate from an electrical device, a field shield electrode is buried in a substrate between the MOSFET and the electrical device so that the bottom surface of the field shield electrode is at a level deeper than each of depth levels of diffusion layers of the MOSFET and the electric device. To provide such an electrode, a trench is formed in a substrate at a level deeper than the depth levels of the diffusion layers of both the MOSFET and the electric device. After insulating an entire inner surface of the trench, an field shield electrode is buried and exposed surface of the electrode is covered with an insulating film.
    Type: Grant
    Filed: June 13, 1994
    Date of Patent: September 17, 1996
    Assignee: Nippon Steel Semiconductor Corporation
    Inventor: Masayuki Hashimoto
  • Patent number: 5532618
    Abstract: A stress mode circuit is provided to generate a voltage that is either equal to a reference voltage or is a proportion of an external voltage (VCCEXT). The circuit includes two voltage divider circuits to provide the proportion voltage. Two differential amplifiers are provided to generate outputs corresponding to a comparison to the proportion voltage and the reference voltage. The outputs operate switches that couple the reference voltage or the proportion voltage to an output terminal.
    Type: Grant
    Filed: November 30, 1992
    Date of Patent: July 2, 1996
    Assignees: United Memories, Inc., Nippon Steel Semiconductor Corporation
    Inventors: Kim C. Hardee, Michael V. Cordoba