Patents Assigned to Monolithic System Technology, Inc.
  • Patent number: 6841821
    Abstract: A non-volatile memory cell is fabricated using a conventional logic process, with minor modifications. The cell is fabricated by forming a shallow trench isolation (STI) region in a well region of a semiconductor substrate. A recessed region is formed in the STI region, wherein the recessed region extends into the STI region and exposes a sidewall region in the well region. A capacitor region is formed in the sidewall region. A dielectric layer is formed over the well region, including the sidewall region. A gate electrode is then formed over the dielectric layer, wherein a portion of the gate electrode extends into the recessed region. An access transistor of the cell is then formed in a self-aligned manner with respect to the gate electrode. A capacitor structure is formed by the gate electrode (in the recessed region), the dielectric layer on the sidewall region, and the capacitor region.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: January 11, 2005
    Assignee: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu
  • Publication number: 20040260983
    Abstract: A fault-tolerant, high-speed wafer scale system comprises a plurality of functional modules, a parallel hierarchical bus which is fault-tolerant to defects in an interconnect network, and one or more bus masters. This bus includes a plurality of bus lines segmented into sections and linked together by programmable bus switches and bus transceivers or repeaters in an interconnect network.
    Type: Application
    Filed: March 11, 2004
    Publication date: December 23, 2004
    Applicant: Monolithic System Technology, Inc.
    Inventors: Wing Yu Leung, Fu-Chieh Hsu
  • Patent number: 6808169
    Abstract: A non-volatile memory (NVM) system includes a NVM cell having: a semiconductor region having a first conductivity type; a gate dielectric layer located over the semiconductor region; a gate electrode located over the gate dielectric layer; a source region and a drain region of a second conductivity type, opposite the first conductivity type, located in the semiconductor region and aligned with the gate electrode; a crown electrode having a base that contacts the gate electrode and walls that extend vertically from the base region, away from the gate electrode; a dielectric layer located over the crown electrode, wherein the dielectric layer extends over at least interior surfaces of the walls; and a plate electrode located over the dielectric layer, wherein the plate electrode extends over at least interior surfaces of the walls.
    Type: Grant
    Filed: September 6, 2001
    Date of Patent: October 26, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Fu-Chieh Hsu, Wingyu Leung
  • Patent number: 6795364
    Abstract: An array of memory cells that require periodic refresh is operated in a single-cell mode during normal operating conditions. Upon receiving an asserted standby control signal from an accessing memory client, the array enters a standby mode from the normal operating conditions. The standby mode can be specified as a differential-cell mode, a single-cell mode or a non-retentive mode. To enter the differential-cell standby mode, data stored in the single-cell mode is converted to a differential-cell mode. In this conversion, half of the data stored in the single-cell mode is saved, while the other half is discarded. In the differential-cell standby mode, refresh operations are performed less frequently than in the normal operating mode, thereby conserving power. The external clock signal provided by the accessing memory client can be disabled during the differential-cell standby mode, as a local clock signal is provided to implement the refresh operations during standby mode.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: September 21, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Jae-Hong Jeong
  • Patent number: 6784048
    Abstract: A memory system that includes a DRAM cell that includes an access transistor and a storage capacitor. The storage capacitor is fabricated by forming a polysilicon crown electrode, a dielectric layer overlying the polysilicon crown, and a polysilicon plate electrode overlying the dielectric layer. A first set of thermal cycles are performed during the formation of the storage capacitor to form and anneal the elements of the capacitor structure. Subsequently, shallow P+ and/or N+ regions are formed by ion implantation, and metal salicide is formed. As a result, the relatively high first set of thermal cycles required to form the capacitor structure does not adversely affect the shallow P+ and N+ regions or the metal salicide. A second set of thermal cycles, which are comparable to or less than the first set of thermal cycles, are performed during the formation of the shallow regions and the metal salicide.
    Type: Grant
    Filed: August 28, 2002
    Date of Patent: August 31, 2004
    Assignee: Monolithic Systems Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Patent number: 6754746
    Abstract: Improved circuitry for connecting the memory array to a data bus allows for high speed accessing of the memory array. Sense amplifier latches are coupled to each column of memory cells. The latched sense amplifiers are coupled to decoders which, in turn, are coupled to data amplifiers. The data amplifiers are coupled to a data bus. Data being read from or written to the memory cells is via the sense amplifier latches, the decoders, and data amplifiers.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: June 22, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Winston Lee, Fu-Chieh Hsu
  • Patent number: 6751157
    Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array requiring periodic refresh operations so that the refresh does not require explicit control signaling nor handshake communication between the memory array and an external accessing client. The method and apparatus handles external accesses and refresh operations such that the refresh operations do not interfere with the external accesses under any conditions. As a result, an SRAM compatible device can be built from DRAM or 1-Transistor cells. A clock division scheme is implemented to perform external accesses during one portion of a clock cycle, and required refresh operations during another portion of the same clock cycle.
    Type: Grant
    Filed: October 23, 2002
    Date of Patent: June 15, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventor: Wingyu Leung
  • Publication number: 20040104407
    Abstract: A vertical one-transistor, floating-body DRAM cell is fabricated by forming an isolation region in a semiconductor substrate, thereby defining a semiconductor island in the substrate. A buried source region is formed in the substrate, wherein the top/bottom interfaces of the buried source region are located above/below the bottom of the isolation region, respectively. A recessed region is etched into the isolation region, thereby exposing sidewalls of the semiconductor island, which extend below the top interface of the buried source region. A gate dielectric is formed over the exposed sidewalls, and a gate electrode is formed in the recessed region, over the gate dielectric. A drain region is formed at the upper surface of the semiconductor island region, thereby forming a floating body region between the drain region and the buried source region. Dielectric spacers are formed adjacent to the gate electrode, thereby covering exposed edges of the gate dielectric.
    Type: Application
    Filed: November 10, 2003
    Publication date: June 3, 2004
    Applicant: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu
  • Patent number: 6744676
    Abstract: A memory system that includes a dynamic random access memory (DRAM) cell including an access transistor and a capacitor structure fabricated in a semiconductor substrate. The capacitor structure is fabricated by forming a cavity in a shallow trench isolation region, thereby exposing a sidewall region of the substrate below the upper surface of the substrate. A dielectric layer is formed over the upper surface and the sidewall region of the substrate. A polysilicon layer is formed over the dielectric layer and patterned to form a capacitor electrode of the capacitor structure that extends over the upper surface and the sidewall region of the substrate. The capacitor electrode is partially recessed below the upper surface of the substrate. The polysilicon layer is also patterned to form the gate electrode of the access transistor.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: June 1, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Patent number: 6732229
    Abstract: A memory redundancy scheme is provided for re-routing data signal paths to disconnect defective memory blocks in a memory array. Each memory block is provided with a corresponding routing unit. Each routing unit is coupled to its corresponding memory block and at least one additional adjacent memory block. The routing units are configured to route data between functional memory blocks and a data bus. The routing units are controlled by configuration values stored in a shifter circuit, which extends through the routing units. To replace a defective memory block, the address of the defective memory block is identified. Configuration values are serially loaded into the shifter circuit, wherein the configuration values are selected in response to the address of the defective memory block.
    Type: Grant
    Filed: February 14, 2000
    Date of Patent: May 4, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Jui-Pin Tang
  • Publication number: 20040061148
    Abstract: A one-transistor, floating-body (1T/FB) dynamic random access memory (DRAM) cell is provided that includes a field-effect transistor fabricated using a process compatible with a standard CMOS process. The field-effect transistor includes a source region and a drain region of a first conductivity type and a floating body region of a second conductivity type, opposite the first conductivity type, located between the source region and the drain region. A buried region of the first conductivity type is located under the source region, drain region and floating body region. The buried region helps to form a depletion region, which is located between the buried region and the source region, the drain region and the floating body region. The floating body region is thereby isolated by the depletion region. A bias voltage can be applied to the buried region, thereby controlling leakage currents in the 1T/FB DRAM cell.
    Type: Application
    Filed: September 30, 2003
    Publication date: April 1, 2004
    Applicant: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu
  • Patent number: 6714470
    Abstract: A semi-conductor memory device having a wide write data bandwidth is provided with high speed read-write circuitry having data amplifiers that are activated to accelerate amplification of write data signals being driven by write data drivers onto data lines of the cell array of the device during memory write cycles, as well as activated to amplify read data signals on the data lines during memory read cycles. Moreover, the data amplifiers are activatedin a self-timed manner. In one embodiment, the device is further provided with a read data buffer that is constituted with a regenerative latch and an input stage, and a write data buffer having multiple entries. The input stage of the read data buffer isolates or couples the regenerative latch to the data lines depending on whether the data lines are in a pre-charged state or not.
    Type: Grant
    Filed: September 25, 2001
    Date of Patent: March 30, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Jui-Pin Tang
  • Patent number: 6707743
    Abstract: A method and apparatus for handling the refresh of a DRAM array or other memory array requiring periodic refresh operations so that the refresh does not require explicit control signaling nor handshake communication between the memory array and an external accessing client. The method and apparatus handles external accesses and refresh operations such that the refresh operations do not interfere with the external accesses under any conditions. As a result, an SRAM compatible device can be built from DRAM or 1-Transistor cells. A clock division scheme is implemented to allow N external accesses and one refresh operation to be performed during N consecutive clock cycles.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: March 16, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Jae-Kwang Sim
  • Patent number: 6686624
    Abstract: A vertical one-transistor, floating-body DRAM cell is fabricated by forming an isolation region in a semiconductor substrate, thereby defining a semiconductor island in the substrate. A buried source region is formed in the substrate, wherein the top/bottom interfaces of the buried source region are located above/below the bottom of the isolation region, respectively. A recessed region is etched into the isolation region, thereby exposing sidewalls of the semiconductor island, which extend below the top interface of the buried source region. A gate dielectric is formed over the exposed sidewalls, and a gate electrode is formed in the recessed region, over the gate dielectric. A drain region is formed at the upper surface of the semiconductor island region, thereby forming a floating body region between the drain region and the buried source region. Dielectric spacers are formed adjacent to the gate electrode, thereby covering exposed edges of the gate dielectric.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: February 3, 2004
    Assignee: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu
  • Patent number: 6661042
    Abstract: A one-transistor, floating-body (1T/FB) dynamic random access memory (DRAM) cell is provided that includes a field-effect transistor fabricated using a process compatible with a standard CMOS process. The field-effect transistor includes a source region and a drain region of a first conductivity type and a floating body region of a second conductivity type, opposite the first conductivity type, located between the source region and the drain region. A buried region of the first conductivity type is located under the source region, drain region and floating body region. The buried region helps to form a depletion region, which is located between the buried region and the source region, the drain region and the floating body region. The floating body region is thereby isolated by the depletion region. A bias voltage can be applied to the buried region, thereby controlling leakage currents in the 1T/FB DRAM cell.
    Type: Grant
    Filed: March 11, 2002
    Date of Patent: December 9, 2003
    Assignee: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu
  • Patent number: 6654295
    Abstract: A memory system that includes a DRAM cell that includes an access transistor and a storage capacitor. The storage capacitor is fabricated by forming a polysilicon crown electrode, a dielectric layer overlying the polysilicon crown, and a polysilicon plate electrode overlying the dielectric layer. A first set of thermal cycles are performed during the formation of the storage capacitor to form and anneal the elements of the capacitor structure. Subsequently, shallow P+ and/or N+ regions are formed by ion implantation, and metal salicide is formed. As a result, the relatively high first set of thermal cycles required to form the capacitor structure does not adversely affect the shallow P+ and N+ regions or the metal salicide. A second set of thermal cycles, which are comparable to or less than the first set of thermal cycles, are performed during the formation of the shallow regions and the metal salicide.
    Type: Grant
    Filed: January 11, 2002
    Date of Patent: November 25, 2003
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Patent number: 6642098
    Abstract: A memory system that includes a dynamic random access memory (DRAM) cell including an access transistor and a capacitor structure fabricated in a semiconductor substrate. The capacitor structure is fabricated by forming a cavity in a shallow trench isolation region, thereby exposing a sidewall region of the substrate below the upper surface of the substrate. A dielectric layer is formed over the upper surface and the sidewall region of the substrate. A polysilicon layer is formed over the dielectric layer and patterned to form a capacitor electrode of the capacitor structure that extends over the upper surface and the sidewall region of the substrate. The capacitor electrode is partially recessed below the upper surface of the substrate. The polysilicon layer is also patterned to form the gate electrode of the access transistor.
    Type: Grant
    Filed: February 25, 2003
    Date of Patent: November 4, 2003
    Assignee: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Publication number: 20030151072
    Abstract: A memory system that includes a dynamic random access memory (DRAM) cell including an access transistor and a capacitor structure fabricated in a semiconductor substrate. The capacitor structure is fabricated by forming a cavity in a shallow trench isolation region, thereby exposing a sidewall region of the substrate below the upper surface of the substrate. A dielectric layer is formed over the upper surface and the sidewall region of the substrate. A polysilicon layer is formed over the dielectric layer and patterned to form a capacitor electrode of the capacitor structure that extends over the upper surface and the sidewall region of the substrate. The capacitor electrode is partially recessed below the upper surface of the substrate. The polysilicon layer is also patterned to form the gate electrode of the access transistor.
    Type: Application
    Filed: February 25, 2003
    Publication date: August 14, 2003
    Applicant: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Publication number: 20030151071
    Abstract: A memory system that includes a dynamic random access memory (DRAM) cell including an access transistor and a capacitor structure fabricated in a semiconductor substrate. The capacitor structure is fabricated by forming a cavity in a shallow trench isolation region, thereby exposing a sidewall region of the substrate below the upper surface of the substrate. A dielectric layer is formed over the upper surface and the sidewall region of the substrate. A polysilicon layer is formed over the dielectric layer and patterned to form a capacitor electrode of the capacitor structure that extends over the upper surface and the sidewall region of the substrate. The capacitor electrode is partially recessed below the upper surface of the substrate. The polysilicon layer is also patterned to form the gate electrode of the access transistor.
    Type: Application
    Filed: February 25, 2003
    Publication date: August 14, 2003
    Applicant: Monolithic System Technology, Inc.
    Inventors: Wingyu Leung, Fu-Chieh Hsu
  • Publication number: 20030147277
    Abstract: A non-volatile memory cell is fabricated using a conventional logic process, with minor modifications. The cell is fabricated by forming a shallow trench isolation (STI) region in a well region of a semiconductor substrate. A recessed region is formed in the STI region, wherein the recessed region extends into the STI region and exposes a sidewall region in the well region. A capacitor region is formed in the sidewall region. A dielectric layer is formed over the well region, including the sidewall region. A gate electrode is then formed over the dielectric layer, wherein a portion of the gate electrode extends into the recessed region. An access transistor of the cell is then formed in a self-aligned manner with respect to the gate electrode. A capacitor structure is formed by the gate electrode (in the recessed region), the dielectric layer on the sidewall region, and the capacitor region.
    Type: Application
    Filed: January 31, 2003
    Publication date: August 7, 2003
    Applicant: Monolithic System Technology, Inc.
    Inventor: Fu-Chieh Hsu