Abstract: Thin film logic circuits employ thin-film switching devices to execute complementary logic functions. Such logic devices operate, as complementary metal oxide semiconductor (CMOS) logic devices do, in a manner that does not provide a direct conduction path between a system supply and a system return. Complementary logic circuits may employ three-terminal threshold switches as switching elements.
Abstract: A method of programming a phase-change material. The method includes providing a transformation pulse to the phase-change material, where the transformation pulse includes a programming waveform and a conditioning waveform. The programming waveform provides sufficient energy to alter the structural state of the phase-change material. In one embodiment, the programming waveform alters the volume fractions of crystalline and amorphous phase regions within the phase-change material. The conditioning waveform provides sufficient energy to heat the phase-change material to a temperature above the ambient temperature but below the crystallization temperature of the phase-change material. The method programs the phase-change material to a state that exhibits a reduced time variation of resistance.
Abstract: An electronic system includes at least one reduced-complexity integrated circuit memory coupled to a memory controller. By reducing the complexity of each integrated circuit memory and concentrating the complexity within the memory controller, overall system costs may be greatly reduced and reliability improved.
Abstract: A memory or switching device includes a mesa and a first electrode conforming to said mesa. The device also includes a second electrode and a phase-change or switching material disposed between said first and second electrodes. The phase-change or switching material is in electrical communication with the first and second electrodes at a first contact region and a second contact region respectively. Also described is a method for making a memory or switching device. The method includes providing a first insulator and configuring the first insulator to provide a mesa. A first conductive layer is provided conforming to the mesa. A phase-change or switching material is provided over a portion of the first conductive layer, and a second conductive layer is provided over the phase-change or switching material.
Abstract: Logic circuits are disclosed that include one or more three-terminal chalcogenide devices. The three-terminal chalcogenide devices are electrically interconnected and configured to perform one or more logic operations, including AND, OR, NOT, NAND, NOR, XOR, and XNOR. Embodiments include series and parallel configurations of three-terminal chalcogenide devices. The chalcogenide devices include a chalcogenide switching material as the working medium along with three electrical terminals in electrical communication therewith. In one embodiment, the circuits include one or more input terminals, one or more output terminals, and a clock terminal. The input terminals receive one or more input signals and deliver them to the circuit for processing according to a logic operation. Upon conclusion of processing, the output of the circuit is provided to the output terminal. The clock terminal delivers a clock signal to facilitate operation of the three-terminal devices included in the instant circuits.
Abstract: Chalcogenide devices are delineated and sidewalls of the devices are sealed, in an anaerobic and/or anhydrous environment environment. Throughout the delineation and sealing steps, and any intervening steps, the sidewalls are not exposed to oxygen or water. In an illustrative embodiment, a cluster tool includes an etching tool and a sealing/deposition tool configured to etch and seal the chalcogenide devices and to maintain the devices in an anaerobic and/or anhydrous environment throughout the process.
Abstract: A non-volatile single-event upset (SEU) tolerant latch is disclosed. The non-volatile SEU tolerant latch includes a first and second inverters connected to each other in a cross-coupled manner. The gates of transistors within the first inverter are connected to the drains of transistors within the second inverter via a first feedback resistor. Similarly, the gates of transistors within the second inverter are connected to the drains of transistors within the first inverter via a second feedback resistor. The non-volatile SEU tolerant latch also includes a pair of chalcogenide memory elements connected to the inverters for storing information.
Type:
Grant
Filed:
November 25, 2008
Date of Patent:
June 21, 2011
Assignees:
BAE Systems Information and Electronic Systems Integration Inc., Ovonyx, Inc.
Inventors:
Bin Li, John C. Rodgers, Nadim F. Haddad
Abstract: A phase change memory includes a volume of phase change material disposed between, and coupled to, two electrodes, with the composition of a region of at least one of the two electrodes or phase change material having been compositionally altered to reduce the programmed volume of the phase change material.
Abstract: A programmable resistance memory employs a feedback control circuit to regulate the programming current supplied to a selected programmable resistance memory element. The programmable resistance memory may be a phase change memory. The feedback control circuit monitors and controls the characteristics of a current pulse employed to program a memory cell.
Abstract: A memory includes an interface through which it provides access to memory cells, such as phase change memory cells. Such access permits circuitry located on a separate integrated circuit to provide access signals, including read and write signals suitable for binary or multi-level accesses.
Abstract: A programmable resistance memory combines multiple cells into a block that includes one or more shared electrodes. The shared electrode configuration provides additional thermal isolation for the active region of each memory cell, thereby reducing the current required to program each memory cell.
Abstract: A nitrogenated carbon electrode suitable for use in a chalcogenide device and method of making the same are described. The electrode comprises nitrogenated carbon and is in electrical communication with a chalcogenide material. The nitrogenated carbon material may be produced by combining nitrogen and vaporized carbon in a physical vapor deposition process.
Abstract: An active material electronic device with a containment layer. The device includes an active chalcogenide, pnictide, or phase-change material in electrical communication with an upper and lower electrode. The device includes a containment layer formed over the active material that prevents escape of volatilized matter from the active material when the device is exposed to high temperatures during fabrication or operation. The containment layer further prevents chemical contamination of the active material by protecting it from reactive species in the processing or ambient environment. Once the containment layer is formed, the device may be subjected to high temperature or chemically aggressive environments without impairing the compositional or structural integrity of the active material.
Abstract: A read current high enough to threshold a phase change memory element may be used to read the element without thresholding the memory element. The higher current may improve performance in some cases. The memory element does not threshold because the element is read and the current stopped prior to triggering the memory element.
Abstract: Chalcogenide materials conventionally used in chalcogenide memory devices and ovonic threshold switches may exhibit a tendency called drift, wherein threshold voltage or resistance changes with time. By providing a compensating material which exhibits an opposing tendency, the drift may be compensated. The compensating material may be mixed into a chalcogenide, may be layered with chalcogenide, may be provided with a heater, or may be provided as part of an electrode in some embodiments. Both chalcogenide and non-chalcogenide compensating materials may be used.
Abstract: An electrical device includes a composite switching material. The composite switching material includes an electrically switchable component and a non-switchable component. In one embodiment, the composite switching material includes a heterogeneous mixture of at least one chalcogenide material and at least one dielectric material. The composite switching material is disposed between two electrodes and the switchable component is transformable from a resistive state to a conductive state upon application of a voltage between the two electrodes, without changing phase.
Abstract: A phase change memory may transition between two crystalline states. In one embodiment, the phase change material is a chalcogenide which transitions between face centered cubic and hexagonal states. Because these states are more stable, they are less prone to drift than the amorphous state conventionally utilized in phase change memories.
Abstract: An asymmetric-threshold three-terminal electronic switching device includes three terminals coupled to a threshold-switching material. A signal applied across first and second terminals affects an electrical characteristic between the second and third electrodes to a greater extent than the same signal applied across the first and third electrodes. The affected electrical characteristic may be a threshold voltage or conductivity, for example.
Abstract: A read reference circuit for a sense amplifier within a chalcogenide memory device is disclosed. The read reference circuit provides a reference voltage level to the sense amplifier for distinguishing between a logical “0” state and a logical “1” state within a chalcogenide memory cell. In conjunction with a precharge circuit, the read reference circuit generates a selectable read reference current to the sense amplifier in order to detect the logical state of the chalcogenide memory cell. The precharge circuit precharges the bitlines of the chalcogenide memory cell before the sense amplifier detects the logical state of the chalcogenide memory cell.
Type:
Grant
Filed:
November 26, 2008
Date of Patent:
March 29, 2011
Assignees:
BAE Systems Information and Electronic Systems Integration Inc., Ovonyx, Inc.
Inventors:
Bin Li, Adam Matthew Bumgarner, Daniel Pirkl
Abstract: A phase change memory may be formed which is amenable to multilevel programming. The phase change material may be formed with a lateral extent which does not exceed the lateral extent of an underlying heater. As a result, the possibility of current bypassing the amorphous phase change material in the reset state is reduced, reducing the programming current that is necessary to prevent this situation. In addition, a more controllable multilevel phase change memory may be formed in some embodiments.