Patent application number | Description | Published |
20080224119 | PHASE CHANGE MEMORY ELEMENT AND METHOD OF MAKING THE SAME - Thin-film phase-change memories having small phase-change switching volume formed by overlapping thin films. Exemplary embodiments include a phase-change memory element, including a first phase change layer having a resistance, a second phase change layer having a resistance, an insulating layer disposed between the first and second phase change layers; and a third phase change layer having a resistance, and coupled to each of the first and second phase change layers, bridging the insulating layer and electrically coupling the first and second phase change layers, wherein the resistance of the third phase change layer is greater than both the resistance of the first phase change layer and the second phase change layer. | 09-18-2008 |
20090014704 | CURRENT CONSTRICTING PHASE CHANGE MEMORY ELEMENT STRUCTURE - A layer of nanopaiticles having a dimension on the order of 10 nm is employed to form a current constricting layer or as a hardmask for forming a current constricting layer from an underlying insulator layer. The nanoparticles are preferably self-aligning and/or self-planarizing on the underlying surface. The current constricting layer may be formed within a bottom conductive plate, within a phase change material layer, within a top conductive plate, or within a tapered liner between a tapered via sidewall and a via plug contains either a phase change material or a top conductive material. The current density of the local structure around the current constricting layer is higher than the surrounding area, thus allowing local temperature to rise higher than surrounding material. The total current required to program the phase change memory device, and consequently the size of a programming transistor, is reduced due to the current constricting layer. | 01-15-2009 |
20090246964 | Etching process for phase-change films - The invention is directed to a method for etching a phase change material layer comprising steps of providing a phase change material layer and performing a first etching process on the phase change material layer. The etching process is performed with an etchant comprising a fluoride-based gas with a concentration of the fluoride-based gas up to 85% of a total volume of the etchant. | 10-01-2009 |
20090251944 | MEMORY CELL HAVING IMPROVED MECHANICAL STABILITY - Memory cells are described along with methods for manufacturing. A memory cell described herein includes a bottom electrode comprising a base portion and a pillar portion on the base portion, the pillar portion and the base portion having respective outer surfaces and the pillar portion having a width less than that of the base portion. A memory element is on a top surface of the pillar portion of the bottom electrode, and a top electrode is on the memory element. A dielectric spacer contacts the outer surface of the pillar portion, the outer surface of the base portion of the bottom electrode self-aligned with an outer surface of the dielectric spacer. | 10-08-2009 |
20090279350 | BIPOLAR SWITCHING OF PHASE CHANGE DEVICE - Memory devices and methods for operating such devices are described herein. A method as described herein includes applying a reset bias arrangement to a memory cell to change the resistance state from the lower resistance state to the higher resistance state. The reset bias arrangement comprises a first voltage pulse. The method further includes applying a set bias arrangement to the memory cell to change the resistance state from the higher resistance state to the lower resistance state. The set bias arrangement comprises a second voltage pulse, the second voltage pulse having a voltage polarity different from that of the first voltage pulse. | 11-12-2009 |
20090323409 | METHODS FOR HIGH SPEED READING OPERATION OF PHASE CHANGE MEMORY AND DEVICE EMPLOYING SAME - Phase change based memory devices and methods for operating described herein overcome the performance limitations of slow set speeds and long recovery times commonly associated with phase change memory devices, enabling high speed operation and extending their usefulness into high speed applications typically filled by DRAM and SRAM memory. | 12-31-2009 |
20100097851 | METHOD FOR PROGRAMMING A MULTILEVEL PHASE CHANGE MEMORY DEVICE - A method of programming a phase change device includes selecting a desired threshold voltage (Vth) and applying a programming pulse to a phase change material in the phase change device. The applying of the programming pulse includes applying a quantity of energy to the phase change material to drive at least a portion of this material above a melting energy level. A portion of the energy applied to the phase change material is allowed to dissipate below the melting energy level. The shape of the energy dissipation from the phase change material is controlled until the energy applied to the phase change material is less than a quenched energy level, to cause the phase change device to have the desired Vth. A remaining portion of the energy applied to the phase change material is allowed to dissipate to an environmental level. | 04-22-2010 |
20100117048 | MEMORY CELL ACCESS DEVICE HAVING A PN-JUNCTION WITH POLYCRYSTALLINE AND SINGLE-CRYSTAL SEMICONDUCTOR REGIONS - A memory device includes a driver comprising a pn-junction in the form of a multilayer stack including a first doped semiconductor region having a first conductivity type, and a second doped semiconductor region having a second conductivity type opposite the first conductivity type, the first and second doped semiconductors defining a pn-junction therebetween, in which the first doped semiconductor region is formed in a single-crystalline semiconductor, and the second doped semiconductor region includes a polycrystalline semiconductor. Also, a method for making a memory device includes forming a first doped semiconductor region of a first conductivity type in a single-crystal semiconductor, such as on a semiconductor wafer; and forming a second doped polycrystalline semiconductor region of a second conductivity type opposite the first conductivity type, defining a pn-junction between the first and second regions. | 05-13-2010 |
20100117049 | MEMORY CELL ACCESS DEVICE HAVING A PN-JUNCTION WITH POLYCRYSTALLINE PLUG AND SINGLE-CRYSTAL SEMICONDUCTOR REGIONS - A memory device includes a driver comprising a pn-junction in the form of a multilayer stack including a first doped semiconductor region having a first conductivity type, and a second doped semiconductor plug having a second conductivity type opposite the first conductivity type, the first and second doped semiconductors defining a pn junction therebetween, in which the first doped semiconductor region is formed in a single-crystalline semiconductor, and the second doped semiconductor region includes a polycrystalline semiconductor. Also, a method for making a memory device includes forming a first doped semiconductor region of a first conductivity type in a single-crystal semiconductor, such as on a semiconductor wafer; and forming a second doped polycrystalline semiconductor region of a second conductivity type opposite the first conductivity type, defining a pn junction between the first and second regions. | 05-13-2010 |
20100148142 | ALUMINUM COPPER OXIDE BASED MEMORY DEVICES AND METHODS FOR MANUFACTURE - Memory devices are described along with methods for manufacturing. A memory device as described herein includes a first electrode and a second electrode. The memory device further includes a diode and an anti-fuse metal-oxide memory element comprising aluminum oxide and copper oxide. The diode and the metal-oxide memory element are arranged in electrical series between the first electrode and the second electrode. | 06-17-2010 |
20100151652 | MULTI-LEVEL MEMORY CELL HAVING PHASE CHANGE ELEMENT AND ASYMMETRICAL THERMAL BOUNDARY - A multi-level, phase change memory cell has first and second thermal isolation materials having different thermal conductivity properties situated in heat-conducting relation to first and second boundaries of the phase change material. Accordingly, when an electrical current is applied to raise the temperature of the memory material, heat is drawn away from the memory material asymmetrically along a line orthogonal to electric field lines between the electrodes. | 06-17-2010 |
20100157665 | MEMORY CELL DEVICE AND PROGRAMMING METHODS - A memory device including a memory cell comprising phase change material is described along with methods for programming the memory device. A method for programming disclosed herein includes determining a data value for the memory cell, and applying a pulse pair to store the data value. The pulse pair includes an initial pulse having a pulse shape adapted to preset the phase change material in the memory cell to a normalizing resistance state, and a subsequent pulse having a pulse shape adapted to set the phase change material from the normalizing resistance state to a resistance corresponding to the determined data value. | 06-24-2010 |
20100193763 | CURRENT CONSTRICTING PHASE CHANGE MEMORY ELEMENT STRUCTURE - A layer of nanoparticles having a dimension on the order of 10 nm is employed to form a current constricting layer or as a hardmask for forming a current constricting layer from an underlying insulator layer. The nanoparticles are preferably self-aligning and/or self-planarizing on the underlying surface. The current constricting layer may be formed within a bottom conductive plate, within a phase change material layer, within a top conductive plate, or within a tapered liner between a tapered via sidewall and a via plug contains either a phase change material or a top conductive material. The current density of the local structure around the current constricting layer is higher than the surrounding area, thus allowing local temperature to rise higher than surrounding material. The total current required to program the phase change memory device, and consequently the size of a programming transistor, is reduced due to the current constricting layer. | 08-05-2010 |
20100276654 | Low Operational Current Phase Change Memory Structures - Memory cells described herein have an increased current density at lateral edges of the active region compared to that of conventional mushroom-type memory cells, resulting in improved operational current efficiency. | 11-04-2010 |
20110080780 | Method for Programming a Multilevel Phase Change Memory Device - A method of programming a phase change device includes selecting a desired threshold voltage (Vth) and applying a programming pulse to a phase change material in the phase change device. The applying of the programming pulse includes applying a quantity of energy to the phase change material to drive at least a portion of this material above a melting energy level. A portion of the energy applied to the phase change material is allowed to dissipate below the melting energy level. The shape of the energy dissipation from the phase change material is controlled until the energy applied to the phase change material is less than a quenched energy level, to cause the phase change device to have the desired Vth. A remaining portion of the energy applied to the phase change material is allowed to dissipate to an environmental level. | 04-07-2011 |
20110180775 | PROGRAMMABLE METALLIZATION CELL WITH ION BUFFER LAYER - A programmable metallization device, comprises a first electrode; a memory layer electrically coupled to the first electrode and adapted for electrolytic formation and destruction of a conducting bridge therethrough; an ion-supplying layer containing a source of ions of a first metal element capable of diffusion into and out of the memory layer; a conductive ion buffer layer between the ion-supplying layer and the memory layer, and which allows diffusion therethrough of said ions; and a second electrode electrically coupled to the ion-supplying layer. Circuitry is coupled to the device to apply bias voltages to the first and second electrodes to induce creation and destruction of conducting bridges including the first metal element in the memory layer. The ion buffer layer can improve retention of the conducting bridge by reducing the likelihood that the first metallic element will be absorbed into the ion supplying layer. | 07-28-2011 |
20110242874 | RESISTIVE MEMORY AND METHOD FOR CONTROLLING OPERATIONS OF THE SAME - A resistive memory and a method for controlling operations of the resistive memory are provided. The resistive memory has a first memory layer, a second memory layer and a medium layer. Each of the first memory layer and the second memory layer is used to store data. The medium layer is formed between the first memory layer and the second memory layer. The method comprises at least a step of measuring a resistance between the first memory layer and the second memory layer, and determining which one of a first state, a second state and a third state is a state of the resistive memory according to the measured resistance. | 10-06-2011 |
20110280058 | NONVOLATILE MEMORY DEVICE - A memory device comprises an array of memory cells each capable of storing multiple bits of data. Each memory cell includes a programmable transistor in series with a resistance switching device. The transistor is switchable between a plurality of different threshold voltages associated with respective memory states. The resistance switching device is configured to be switchable between a plurality of different resistances associated with respective memory states. | 11-17-2011 |
20110286258 | NONVOLATILE MEMORY DEVICE HAVING A TRANSISTOR CONNECTED IN PARALLEL WITH A RESISTANCE SWITCHING DEVICE - A memory device comprises an array of memory cells each capable of storing multiple bits of data. The memory cells are arranged in memory strings that are connected to a common source line. Each memory cell includes a programmable transistor connected in parallel with a resistance switching device. The transistor is switchable between a plurality of different threshold voltages associated with respective memory states. The resistance switching device is configured to be switchable between a plurality of different resistances associated with respective memory states. | 11-24-2011 |
20120080657 | LOW OPERATIONAL CURRENT PHASE CHANGE MEMORY STRUCTURES - Memory cells described herein have an increased current density at lateral edges of the active region compared to that of conventional mushroom-type memory cells, resulting in improved operational current efficiency. As a result, the amount of heat generated within the lateral edges per unit value of current is increased relative to that of conventional mushroom-type memory cells. Therefore, the amount of current needed to induce phase change is reduced. | 04-05-2012 |
20120181499 | QUATERNARY GALLIUM TELLURIUM ANTIMONY (M-GaTeSb) BASED PHASE CHANGE MEMORY DEVICES - A phase change material comprising a quaternary GaTeSb material consisting essentially of M | 07-19-2012 |