Abstract: A method of testing a programmable resistance memory element. The method includes applying a plurality of reset pulses to the memory element. Each of the reset pulses having an energy which is greater than the minimum energy needed to program the memory element from its set state to its reset state.
Type:
Grant
Filed:
October 7, 2004
Date of Patent:
February 5, 2008
Assignee:
Ovonyx, Inc.
Inventors:
Sergey A. Kostylev, Tyler Lowrey, Wolodymyr Czubatyj
Abstract: An elevated phase-change memory cell facilitates manufacture of phase-change memories by physically separating the fabrication of the phase-change memory components from the rest of the semiconductor substrate. In one embodiment, a contact in the substrate may be electrically coupled to a cup-shaped conductor filled with an insulator. The conductor couples current up to the elevated pore while the insulator thermally and electrically isolates the pore.
Abstract: A phase change memory has an array formed by a plurality of cells, each including a memory element of calcogenic material and a selection element connected in series to the memory element; a plurality of address lines connected to the cells; a write stage and a reading stage connected to the array. The write stage is formed by current generators, which supply preset currents to the selected cells so as to modify the resistance of the memory element. Reading takes place in voltage, by appropriately biasing the selected cell and comparing the current flowing therein with a reference value.
Abstract: A lower electrode may be covered by a protective film to reduce the exposure of the lower electrode to subsequent processing steps or the open environment. As a result, materials that may have advantageous properties as lower electrodes may be utilized despite the fact that they may be sensitive to subsequent processing steps or the open environment.
Abstract: Briefly, in accordance with an embodiment of the invention, a method to manufacture a phase change memory is provided. The method may include forming a first electrode contacting the sidewall surface and the bottom surface of the phase change material. The method may further include forming a second electrode contacting the top surface of the phase change material.
Abstract: A phase change memory may be read so as to reduce the likelihood of a read disturb. A read disturb may occur, for example, when a reset device is raised to a voltage, which causes its threshold device to trigger. The triggering of the threshold device produces a displacement current which may convert a reset device to a set device. By ensuring that the reset cell never reaches a voltage that would result in triggering of the threshold device, read disturbs may be reduced.
Type:
Grant
Filed:
April 14, 2005
Date of Patent:
October 9, 2007
Assignee:
Ovonyx, Inc.
Inventors:
Sergey A. Kostylev, Tyler Arthur Lowrey, Wolodymyr Czubatyj, Ward D. Parkinson
Abstract: A process for defining a chalcogenide material layer using a chlorine based plasma and a mask, wherein the portions of the chalcogenide material layer that are not covered by the mask are etched away. In a phase change memory cell having a stack of a chalcogenide material layer and an AlCu layer, the AlCu layer is etched first using a chlorine based plasma at a higher temperature; then the lateral walls of the AlCu layer are passivated; and then the chalcogenide material layer is etched at a lower temperature.
Type:
Grant
Filed:
April 30, 2004
Date of Patent:
August 14, 2007
Assignees:
STMicroelectronics S.r.l., OVONYX, Inc.
Abstract: The process for forming a film of TiSiN includes the following sequence of steps: deposition of a TiN film at medium temperature, for example, 300-450° C., by thermal decomposition of a metallorganic precursor, for example TDMAT (Tetrakis Dimethylamino Titanium); exposition to a silicon releasing gas, such as silane (SiH4) and dichlorosilane (SiH2Cl2) at 10-90 sccm—standard cube centimeters per minute—for a quite long time, for example, longer than 10 s but less than 90 s, preferably about 40 s; exposition to a H2/N2 plasma at 200-800 sccm, for 10-90 s, preferably about 40 s.
Type:
Grant
Filed:
May 25, 2004
Date of Patent:
August 7, 2007
Assignees:
STMicroelectronics S.r.l., OVONYX, Inc.
Abstract: A process for forming a tapered trench in a dielectric material includes the steps of forming a dielectric layer on a semiconductor wafer, and plasma etching the dielectric layer; during the plasma etch, the dielectric layer is chemically and physically etched simultaneously.
Type:
Grant
Filed:
December 20, 2004
Date of Patent:
July 24, 2007
Assignees:
STMicroelectronics S.r.l., OVONYX, Inc.
Abstract: A process for manufacturing a phase change memory cell, comprising the steps of: forming a resistive element; forming a delimiting structure having an aperture over the resistive element; forming a memory portion of a phase change material in the aperture, the resistive element and the memory portion being in direct electrical contact and defining a contact area of sublithographic extension. The step of forming a memory portion further includes filling the aperture with the phase change material and removing from the delimiting structure an exceeding portion of the phase change material exceeding the aperture.
Type:
Grant
Filed:
April 14, 2004
Date of Patent:
July 17, 2007
Assignees:
STMicroelectronics S.r.l., OVONYX, Inc.
Abstract: A contact structure, including a first conducting region having a first thin portion with a first sublithographic dimension in a first direction; a second conducting region having a second thin portion with a second sublithographic dimension in a second direction transverse to said first direction; the first and second thin portions being in direct electrical contact and defining a contact area having a sublithographic extension. The thin portions are obtained using deposition instead of lithography: the first thin portion is deposed on a wall of an opening in a first dielectric layer; the second thin portion is obtained by deposing a sacrificial region on vertical wall of a first delimitation layer, deposing a second delimitation layer on the free side of the sacrificial region, removing the sacrificial region to form a sublithographic opening that is used to etch a mold opening in a mold layer and filling the mold opening.
Type:
Grant
Filed:
December 5, 2002
Date of Patent:
June 5, 2007
Assignees:
STMicroelectronics S.r.l., Ovonyx, Inc.
Abstract: A content addressable memory cell for a non-volatile content addressable memory, including a non-volatile storage element for storing a content digit, a selection input for selecting the memory cell, a search input for receiving a search digit, and a comparison circuit arrangement for comparing the search digit to the content digit and for driving a match output of the memory cell so as to signal a match between the content digit and the search digit. The non-volatile storage element include at least one phase-change memory element for storing in a non-volatile way the respective content digit.
Type:
Grant
Filed:
October 20, 2004
Date of Patent:
June 5, 2007
Assignees:
STMicroelectronics S.r.l., Ovonyx, Inc.
Inventors:
Guido De Sandre, Roberto Bez, Fabio Pellizzer
Abstract: An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.
Abstract: A cell array is formed by a plurality of cells each including a selection bipolar transistor and a storage component. The cell array is formed in a body including a common collector region of P type; a plurality of base regions of N type, overlying the common collector region; a plurality of emitter regions of P type formed in the base regions; and a plurality of base contact regions of N type and a higher doping level than the base regions, formed in the base regions, wherein each base region is shared by at least two adjacent bipolar transistors.
Type:
Application
Filed:
October 19, 2006
Publication date:
May 3, 2007
Applicants:
STMicroelectronics S.r.l., Ovonyx Inc.
Inventors:
Fabio Pellizzer, Giulio Casagrande, Roberto Bez
Abstract: A memory device having a reading configuration and including a plurality of memory cells, arranged in rows and columns, memory cells arranged on the same column having respective first terminals connected to a same bit line and memory cells arranged on the same row having respective second terminals selectively connectable to a same word line; a supply line providing a supply voltage; a column addressing circuit and a row addressing circuit for respectively addressing a bit line and a word line corresponding to a memory cell selected for reading in the reading configuration. The column addressing circuit is configured to bias the addressed bit line corresponding to the selected memory cell substantially at the supply voltage in the reading configuration.
Abstract: Phase change memories may exhibit improved properties and lower cost in some cases by forming the phase change material layers in a planar configuration. A heater may be provided below the phase change material layers to appropriately heat the material to induce the phase changes. The heater may be coupled to an appropriate conductor.
Type:
Grant
Filed:
December 15, 2004
Date of Patent:
March 27, 2007
Assignee:
Ovonyx, Inc.
Inventors:
Chien Chiang, Charles Dennison, Tyler Lowrey
Abstract: A process for manufacturing a phase change memory cell, comprising the steps of: forming a resistive element; forming a delimiting structure having an aperture over the resistive element; forming a memory portion of a phase change material in the aperture, the resistive element and the memory portion being in direct electrical contact and defining a contact area of sublithographic extension. The step of forming a memory portion further includes filling the aperture with the phase change material and removing from the delimiting structure an exceeding portion of the phase change material exceeding the aperture.
Type:
Application
Filed:
April 14, 2004
Publication date:
March 15, 2007
Applicants:
STMicroelectronics S.r.l., OVONYX Inc.
Abstract: An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.
Abstract: A memory includes a storage element (OUM) made of a phase-change material for storing a logic value and an access element (OTS) switching from a higher resistance condition to a lower resistance condition in response to a selection of the memory cell, the access element in the higher resistance condition decoupling the storage element from a read circuit and in the lower resistance condition coupling the storage element to the read circuit. The read circuit includes a sense amplifier to determine the logic value stored in the memory cell according to an electrical quantity associated with the memory cell. The read circuit further includes a detector that detects the switching of the access element by comparison to a delayed waveform or sensing a change in the column rate of change, and a circuit to enable the sense amplifier in response to the detection of the switching of the access element.
Type:
Grant
Filed:
March 30, 2005
Date of Patent:
December 26, 2006
Assignee:
Ovonyx, Inc.
Inventors:
Ferdinando Bedeschi, Claudio Resta, Ward D. Parkinson, Roberto Gastaldi