Patents Represented by Attorney Thomas W. Leffert
  • Patent number: 6441428
    Abstract: Floating-gate memory cells having a control gate for coupling to a word line, a floating gate, a first source/drain region for coupling to a bit line, and a floating second source/drain region are adapted for use in flash memory devices. Such floating-gate memory cells eliminate the need to provide electrical contact to the second source/drain region, thus simplifying the fabrication process and array architecture. The floating-gate memory cells may be programmed using band-to-band tunneling. The floating-gate memory cells may be read using capacitance sensing or forward current sensing techniques.
    Type: Grant
    Filed: March 19, 2001
    Date of Patent: August 27, 2002
    Assignee: Micron Technology, Inc.
    Inventor: Ramin Ghodsi
  • Patent number: 6424576
    Abstract: Output driver stages and operation modes for selectively disabling device outputs are adapted for use in integrated circuit devices and in the testing of such integrated circuit devices. A device output is disabled by disabling its associated output driver. A first control signal is generated that is indicative of whether an output driver should be responsive to a second control signal or disabled regardless of the second control signal. The first control signal may be provided directly to one or more output drivers. Alternatively, the first control signal may be combined with the second control signal. The first control signal may be common to all coupled output drivers or a separate first control signal may be provided for each output driver. Selective disabling of output drivers can be used to force a device time-out during testing. Selective disabling of output drivers can also be used to reduce device power requirements.
    Type: Grant
    Filed: March 8, 2001
    Date of Patent: July 23, 2002
    Assignee: Micron Technology, Inc.
    Inventors: Jeffrey Antosh, Rex Jackson
  • Patent number: 6396728
    Abstract: Memory devices including blocks of memory cells arranged in columns, with each column of memory cells coupled to a main bit line, are organized for high-speed access and tight packing. Such memory devices include sector bit lines having multiple main bit lines selectively coupled to each sector bit line, with each sector bit line extending to main bit lines in each memory block of a memory sector. Sector bit lines are coupled to sensing devices and the output of each sensing device is selectively coupled to a global bit line, with each global bit line selectively coupled to more than one sensing device. The global bit lines are multiplexed and input to helper flip-flops for output to the data output register of the memory device. Various embodiments include non-volatile, and, particularly, synchronous non-volatile memory devices having multiple banks containing multiple sectors of such memory blocks.
    Type: Grant
    Filed: July 28, 2000
    Date of Patent: May 28, 2002
    Assignee: Micron Technology, Inc.
    Inventors: Ebrahim Abedifard, Frankie F. Roohparvar
  • Patent number: 6370070
    Abstract: Memory devices having architectures permitting the application of a voltage differential across alternate bitlines facilitate identifying and locating shorts within the memory device with particular reference to flash memory devices. The memory devices include a first plurality of selective coupling devices coupled between a first plurality of bitlines and a first variable potential node. The memory devices further include a second plurality of selective coupling devices coupled between a second plurality of bitlines and a second variable potential node. The first plurality of selective coupling devices are responsive to a first control signal to selectively provide electrical communication between the first plurality of bitlines and the first variable potential node. The second plurality of selective coupling devices are responsive to a second control signal to selectively provide electrical communication between the second plurality of bitlines and the second variable potential node.
    Type: Grant
    Filed: June 21, 2001
    Date of Patent: April 9, 2002
    Assignee: Micron Technology, Inc.
    Inventors: Christophe J. Chevallier, Benjamin Louie
  • Patent number: 6366489
    Abstract: Bi-state ferroelectric-MOS (FMOS) capacitors are adapted for use in memory cells of a memory device. Bi-state ferroelectric memory cells have a bottom plate of a capacitor coupled to a first source/drain region of a pass transistor, a gate of the pass transistor coupled to a word line, and a second source/drain region of the pass transistor coupled to a bit line. A plate line is coupled to the top plate of the capacitor to facilitate programming of the polarization state of a ferroelectric portion of the capacitor. The polarization state of the ferroelectric portion of the capacitor causes a depletion or accumulation of electrons in the bottom plate of the capacitor, thus altering its capacitance value. The resulting capacitance value may be sensed without causing a polarization reversal of the ferroelectric portion of the capacitor. Accordingly, bi-state ferroelectric memory cells of the various embodiments function as non-volatile memory cells.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: April 2, 2002
    Assignee: Micron Technology, Inc.
    Inventor: Craig T. Salling
  • Patent number: 6304504
    Abstract: Memory devices having architectures permitting the application of a voltage differential across alternate bitlines facilitate identifying and locating shorts within the memory device with particular reference to flash memory devices. The memory devices include a first plurality of selective coupling devices coupled between a first plurality of bitlines and a first variable potential node. The memory devices further include a second plurality of selective coupling devices coupled between a second plurality of bitlines and a second variable potential node. The first plurality of selective coupling devices are responsive to a first control signal to selectively provide electrical communication between the first plurality of bitlines and the first variable potential node. The second plurality of selective coupling devices are responsive to a second control signal to selectively provide electrical communication between the second plurality of bitlines and the second variable potential node.
    Type: Grant
    Filed: August 30, 2000
    Date of Patent: October 16, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Christophe J. Chevallier, Benjamin Louie
  • Patent number: 6304488
    Abstract: Negative switch circuits are arranged to have a first electrical path coupled between an input and an output of the negative switch circuit and a second electrical path in parallel with the first electrical path for selectively isolating a load from a negative potential node. The first electrical path presents an open circuit in response to a first state of a first control signal and presents a closed circuit in response to a second state of the first control signal. The second electrical path presents an open circuit in response to either a first state of a second control signal or a condition of the load indicative of a defect associated with the load, and presents a closed circuit in response to a second state of the second control signal in combination with a condition of the load not indicative of such a defect. Such negative switch circuits are adaptable to isolate defective portions of a memory device from a negative charge pump during block erase operations.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: October 16, 2001
    Assignee: Micron Technology, Inc.
    Inventors: Ebrahim Abedifard, Frankie F. Roohparvar
  • Patent number: 6275446
    Abstract: Clock generator circuits containing a delay circuit having at least one delay element and at least one bypass are arranged to activate the bypass in response to a first logic level presented at the input of the delay circuit and to deactivate the bypass in response to a second logic level presented at the input of the delay circuit. Such clock generators are useful in synchronous memory devices for generating internal clock signals of fixed pulse width from an external clock signal. The internal clock signal is generated from a triggering event, such as a rising edge of the external clock signal, and has a pulse width determined by the delay time of the delay element. The first logic level is generated in response to the beginning of an output pulse of the clock generator while the second logic level is generated in response to the completion of an output pulse of the clock generator.
    Type: Grant
    Filed: August 25, 2000
    Date of Patent: August 14, 2001
    Assignee: Micron Technology, Inc.
    Inventor: Ebrahim Abedifard