Patents by Inventor Sang H. Dhong

Sang H. Dhong 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: 4954854
    Abstract: A structure and fabrication process for a self-aligned, lightly-doped drain/source n-channel field-effect transistor wherein a trench is formed in a well region in a wafer including an epitaxial layer on a substrate. A first, heavily doped drain region and bit line element is formed around the trench on the surface of the well, and a second, lightly-doped drain region is formed proximate to the first drain region and self-aligned to the trench sidewalls. A source region is located beneath the trench, which is filled with polysilicon, above which is gate and further polysilicon forming a transfer wordline. The well region at the trench sidewalls are doped to control the device threshold level, and the device is thereby also located at a wordline/bitline cross-point.
    Type: Grant
    Filed: May 22, 1989
    Date of Patent: September 4, 1990
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Wei Hwang, Nicky Chau-Chun Lu
  • Patent number: 4954731
    Abstract: Two embodiments of a wordline boost clock circuit that can be used in high speed DRAM circuits are disclosed. The clock circuits require only one boost capacitor and discharge the wordlines faster, improving the DRAM access time. The basic feature of the clock circuit is in the floating gate structure of the nmos device which drives the load to negative during the boosting. In the first embodiment of the clock, the gate of a first device is connected to a first node through a second device. A second node, connected to a wordline, is discharged through the first and a third device when a third node is high with a fourth node low. After a sufficient discharge of the second node, the fourth node is pulled to VDD turning the second device on and a fourth device off. The first (NMOS) transistor has its gate and drain connected together and forms a diode.
    Type: Grant
    Filed: April 26, 1989
    Date of Patent: September 4, 1990
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Wei Hwang, Nicky C. Lu
  • Patent number: 4927779
    Abstract: A complementary MOS one-capacitor dynamic RAM cell which operates with a non-boosted wordline without a threshold loss problem and which includes one storage capacitor and n- and p-type transfer devices connected to the storage capacitor which function as two complementary transistor devices having gates controlled by complementary signals on the RAM wordlines.
    Type: Grant
    Filed: October 27, 1989
    Date of Patent: May 22, 1990
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Nicky C. Lu, Walter H. Henkels
  • Patent number: 4922128
    Abstract: A boost clock signal generator which provides a boost clock signal from a pair of phase clocks. A pair of differentially-connected FET transistors which generate a boost clock signal. The transistors have drain connections connected to each of two clock signals, and commonly connected sources which form an output terminal for the boost clock signal. A series pass FET transistor is connected with each gate of the differential transistors for maintaining the gate at a floating voltage potential. A pair of capacitive elements couple the drain of each pair of differentially-connected FET transistors to the gate of an opposite transistor. A first and second logic circuit are connected to the series pass FET transistors for enabling one or the other of the differnetially-connected FET transistors into conduction.
    Type: Grant
    Filed: January 13, 1989
    Date of Patent: May 1, 1990
    Assignee: IBM Corporation
    Inventors: Sang H. Dhong, Wei Hwang, Nicky C. Lu
  • Patent number: 4920065
    Abstract: This invention relates generally to dynamic random access, semiconductor memory arrays and more specifically relates to an ultra dense dynamic random access memory array. It also relates to a method of fabricating such arrays using a plurality of etch and refill steps which includes a differential etching step which is a key step in forming insulating conduits which themselves are adapted to hold a pair of field effect transistor gates of the adjacent transfer devices of one device memory cells. The differential etch step provides spaced apart device regions and an insulation region of reduced height between the trenches which space apart the memory cells. The resulting structure includes a plurality of rows of vertically arranged field effect transistors wherein the substrate effectively acts as a counterelectrode surrounding the insulated drain regions of each of the one device memory cells. A pair of gates are disposed in insulating conduits which run perpendicular to the rows of memory cells.
    Type: Grant
    Filed: October 27, 1989
    Date of Patent: April 24, 1990
    Assignee: International Business Machines Corporation
    Inventors: Daeje Chin, Sang H. Dhong
  • Patent number: 4910709
    Abstract: A complementary MOS one-capacitor dynamic RAM cell which operates with a non-boosted wordline without a threshold loss problem and which includes one storage capacitor and n- and p-type transfer devices connected to the storage capacitor which function as two complementary transistor devices having gates controlled by complementary signals on the RAM wordlines.
    Type: Grant
    Filed: August 10, 1988
    Date of Patent: March 20, 1990
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Nicky C. Lu, Walter H. Henkels
  • Patent number: 4894697
    Abstract: This invention relates generally to dynamic random access, semiconductor memory arrays and more specifically relates to an ultra dense dynamic random access memory array. It also relates to a method of fabricating such arrays using a plurality of etch and refill steps which includes a differential etching step which is a key step in forming insulating conduits which themselves are adapted to hold a pair of field effect transistor gates of the adjacent transfer devices of one device memory cells. The differential etch step provides spaced apart device regions and an insulation region of reduced height between the trenches which space apart the memory cells. The resulting structure includes a plurality of rows of vertically arranged field effect transistors wherein the substrate effectively acts as a counterelectrode surrounding the insulated drain regions of each of the one device memory cells. A pair of gates are disposed in insulating conduits which run perpendicular to the rows of memory cells.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: January 16, 1990
    Assignee: International Business Machines Corporation
    Inventors: Daeje Chin, Sang H. Dhong
  • Patent number: 4816706
    Abstract: A novel sense amplifier and decoupling device structure for integrated circuit memories wherein an embodiment of a cross-coupled sense amplifier includes two PMOS devices, the gates of which devices are grounded and clamp the downward voltage swing of the memory bitlines to the absolute value of the threshold voltage (VTP) of the grounded-gate PMOS devices in the sense amplifier. This limited voltage swing does not affect charge storage of storage capacitors because the absolute value of the threshold voltage (VT) of the cell transfer gate device is larger. Precharging the bitlines is achieved by equalizing the two bitlines, each charged to VDD and .vertline.VTP.vertline., respectively. One node of the sense amplifier retains a full VDD swing and is conveniently connected to the DATA bus. The sense amplifier bitline swing is limited to a swing of VDD-.vertline.VTP.vertline.
    Type: Grant
    Filed: September 10, 1987
    Date of Patent: March 28, 1989
    Assignee: International Business Machines Corporation
    Inventors: Sang H. Dhong, Nicky C. C. Lu