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Bipin Rajendran, White Plains US

Bipin Rajendran, White Plains, NY US

Patent application numberDescriptionPublished
20090013146METHOD TO CREATE A UNIFORMLY DISTRIBUTED MULTI-LEVEL CELL (MLC) BITSTREAM FROM A NON-UNIFORM MLC BITSTREAM - A method, system, and computer software product for operating a collection of memory cells. Each memory cell in the collection of memory cells is configured to store a binary multi-bit value delimited by characteristic parameter bands. In one embodiment, a transforming unit transforms an original collection of data to a transformed collection of data using a reversible mathematical operator. The original collection of data has binary multi-bit values arbitrarily distributed across the binary multi-bit values assigned to the characteristic parameter bands and the transformed collection of data has binary multi-bit values substantially uniformly distributed across the binary multi-bit values assigned to the characteristic parameter bands.01-08-2009
20090052230INTEGRATED CIRCUIT INCLUDING SILICIDE REGION TO INHIBIT PARASITIC CURRENTS - An integrated circuit is disclosed. One embodiment includes a first diode, a second diode, and a semiconductor line coupled to the first diode and the second diode. The line includes a first silicide region between the first diode and the second diode.02-26-2009
20090073783MULTI-LEVEL MEMORY CELL UTILIZING MEASUREMENT TIME DELAY AS THE CHARACTERISTIC PARAMETER FOR LEVEL DEFINITION - A memory array and computer program product for operating a memory cell and memory array. An embodiment of the invention entails receiving a request to read a binary value stored in the memory cell. A pre-charging operation pre-charges a bit-line capacitor in an electronic circuit formed by the memory cell to a pre-charge voltage. A word-line in the electronic circuit is then activated. A discharging operation discharges the bit-line capacitor through the said memory cell in the electronic circuit to the word-line. Additionally, an electron discharge time measurement is started when the word-line is activated. The electron discharge time measurement is stopped when the voltage level in the bit-line falls below a pre-defined reference voltage. A determining operation determines the binary value from the measured electron discharge time.03-19-2009
20090073784MULTI-LEVEL MEMORY CELL UTILIZING MEASUREMENT TIME DELAY AS THE CHARACTERISTIC PARAMETER FOR LEVEL DEFINITION - A memory array and computer program product for operating a memory cell and memory array. An embodiment of the invention entails receiving a binary value to be stored by a memory cell. A determining operation determines a target discharge time corresponding to the binary value. The target discharge time being the time needed to discharge a pre-charged circuit through the said memory cell to a predetermined level. A storing operation stores a characteristic parameter in the memory cell such that an electron discharge time through an electronic circuit formed, at least partially, by the memory cell, is substantially equal to the target discharge time.03-19-2009
20090073790MULTI-LEVEL MEMORY CELL UTILIZING MEASUREMENT TIME DELAY AS THE CHARACTERISTIC PARAMETER FOR LEVEL DEFINITION - A method for operating a memory cell and memory array. The method of memory cell operation entails receiving a request to read a binary value stored in the memory cell. A pre-charging operation pre-charges a bit-line capacitor in an electronic circuit formed by the memory cell to a pre-charge voltage. A word-line in the electronic circuit is then activated. A discharging operation discharges the bit-line capacitor through the said memory cell in the electronic circuit to the word-line. Additionally, an electron discharge time measurement is started when the word-line is activated. The electron discharge time measurement is stopped when the voltage level in the bit-line falls below a pre-defined reference voltage. A determining operation determines the binary value from the measured electron discharge time.03-19-2009
20090173928POLYSILICON EMITTER BJT ACCESS DEVICE FOR PCRAM - A resistive non-volatile memory cell with a bipolar junction transistor (BJT) access device formed in conjunction with the entire memory cell. The memory cell includes a substrate acting as a collector, a semiconductor base layer acting as a base, and a semiconductor emitter layer acting as an emitter. Additionally, metal plugs and the phase change memory element are formed above the BJT access device while the emitter, metal plugs, and phase change memory element are contained within an insulating region. In one embodiment of the invention, a spacer layer is formed and the emitter layer is contained within the protective spacer layer. The spacer layer is contained within the insulating region.07-09-2009
20090175071PHASE CHANGE MEMORY DYNAMIC RESISTANCE TEST AND MANUFACTURING METHODS - A method for testing an integrated circuit memory device includes applying a sequence of test pulses to a memory cell on the device, where the test pulses result in current through the memory cell having an amplitude dependent on the test pulse. Resistance in the memory cell is measured in response to the sequence of test pulses. A parameter set is extracted from the resistance measurements which includes at least one numerical coefficient that models dependency of the measured resistance on the amplitude of the current through the memory cell. The extracted numerical coefficient or coefficients are associated with the memory device, and used for controlling manufacturing operations.07-09-2009
20090176354METHOD FOR FABRICATION OF SINGLE CRYSTAL DIODES FOR RESISTIVE MEMORIES - The present invention, in one embodiment, provides a method of producing a PN junction the method including providing a single crystal substrate; forming an insulating layer on the single crystal substrate; forming a via through the insulating layer to provide an exposed portion of the single crystal substrate; forming amorphous Si on at least the exposed portion of the single crystal substrate; converting at least a portion of the amorphous Si into single crystal Si; and forming dopant regions in the single crystal Si. In one embodiment the diode of the present invention is integrated with a memory device.07-09-2009
20090185411INTEGRATED CIRCUIT INCLUDING DIODE MEMORY CELLS - The integrated circuit includes a first metal line and a first diode coupled to the first metal line. The integrated circuit includes a first resistivity changing material coupled to the first diode and a second metal line coupled to the first resistivity changing material.07-23-2009
20090200534METHOD FOR FABRICATION OF POLYCRYSTALLINE DIODES FOR RESISTIVE MEMORIES - The present invention, in one embodiment, provides a method of producing a PN junction the method including at least the steps of providing a Si-containing substrate; forming an insulating layer on the Si-containing substrate; forming a via through the insulating layer to expose at least a portion of the Si-containing substrate; forming a seed layer of the exposed portion of the Si containing substrate; forming amorphous Si on at least the seed layer; converting at least a portion of the amorphous Si to provide crystalline Si; and forming a first dopant region abutting a second dopant region in the crystalline Si.08-13-2009
20090242865MEMORY ARRAY WITH DIODE DRIVER AND METHOD FOR FABRICATING THE SAME - A method of fabricating a memory array. The method begins with a structure, generally composed of dielectric fill material and having conductive lines formed at its lower portion, and a sacrificial layer formed on its upper surface. Diodes are formed in the fill material, each diode having a lightly-doped first layer of the same conductivity type as the conductive lines; a heavily doped second layer of opposite conductivity type; and a conductive cap. Self-aligned vias are formed over the diodes. Self-aligned, and self-centered spacers in the self-aligned vias define pores that expose the conductive cap. Memory material is deposited within the pores, the memory material making contact with the conductive cap. A top electrode is formed in contact with the memory material.10-01-2009
20090268507PHASE CHANGE MEMORY DEVICE AND METHOD OF MANUFACTURE - A phase change memory control ring lower electrode is disclosed. The lower electrode includes an outer ring electrode in thermal contact with a phase change memory element, an inner seed layer disposed within the outer ring electrode and in contact with the phase change memory element, and an electrically conductive bottom layer coupled to the outer ring electrode.10-29-2009
20090286368 PROCESS FOR PCM INTEGRATION WITH POLY-EMITTER BJT AS ACCESS DEVICE - Techniques for forming a memory cell. An aspect of the invention includes forming FET gate stacks and sacrificial cell gate stacks over the substrate. Spacer layers are then formed around the FET gate stacks and around the sacrificial cell gate stacks. The sacrificial cell gate stacks are then removed such that the spacer layers around the sacrificial cell gate stacks are still intact. BJT cell stacks are then formed in the space between the spacer layers where the sacrificial cell gate stacks were formed and removed, the BJT cell stacks including an emitter layer. A phase change layer above the emitter contacts and an electrode above the phase change layer are then formed.11-19-2009
20090316473INTEGRATED CIRCUIT INCLUDING VERTICAL DIODE - An integrated circuit includes a substrate including isolation regions, a first conductive line formed in the substrate between isolation regions, and a vertical diode formed in the substrate. The integrated circuit includes a contact coupled to the vertical diode and a memory element coupled to the contact. The first conductive line provides a portion of the vertical diode.12-24-2009
20090323384HIGH DENSITY CONTENT ADDRESSABLE MEMORY USING PHASE CHANGE DEVICES - A content addressable memory array storing stored words in memory elements. Each memory element stores one of at least two complementary binary bits as one of at least two complementary resistances. Each memory element is electrically coupled to an access device. An aspect of the content addressable memory array is the use of a biasing circuit to bias the access devices during a search operation. During the search operation, a search word containing a bit string is received. Each access device is biased to a complementary resistance value of a corresponding search bit in the search word. A match between the search word and stored word is indicated if the bits stored in the memory elements are complementary to the bits represented by the resistances in the access devices.12-31-2009
20100002481CONTENT ADDRESSABLE MEMORY USING PHASE CHANGE DEVICES - Content addressable memory device utilizing phase change devices. An aspect of the content addressable memory device is the use of a comparatively lower power search-line access element and a comparatively higher power word-line access element. The word-line access element is only utilized during write operations and the search-line access element is only utilized during search operations. The word-line access element being electrically coupled to a second end of a phase change memory element and a word-line. The search-line access element also being electrically coupled to the second end of the phase change memory element and a search-line. The search-line being electrically coupled to a match-line. A bit-line is electrically coupled to a first end of the phase change memory element. Additionally, a complementary set of access elements, a complementary phase change memory element, a complementary search-line, and a complementary bit-line are also included in the content addressable memory device.01-07-2010
20100048020Nanoscale Electrodes for Phase Change Memory Devices - A process for preparing a phase change memory semiconductor device comprising a (plurality of) nanoscale electrode(s) for alternately switching a chalcogenide phase change material from its high resistance (amorphous) state to its low resistance (crystalline) state, whereby a reduced amount of current is employed, and wherein the plurality of nanoscale electrodes, when present, have substantially the same dimensions.02-25-2010
20100078621METHOD TO REDUCE RESET CURRENT OF PCM USING STRESS LINER LAYERS - A memory cell structure and method for forming the same. The method includes forming a via within a dielectric layer. The via is formed over the center of an electrically conducting bottom electrode. The method includes depositing a stress liner along at least one sidewall of the via. The stress liner imparting stress on material proximate the stress liner. In one embodiment, the stress liner provides a stress in the range of 500 to 5000 MPa on the material enclosed within its volume. The method includes depositing phase change material within the via and the volume enclosed by the stress liner. The method also includes forming an electrically conducting top electrode above the phase change material.04-01-2010
20100135085MULTI-LEVEL MEMORY CELL UTILIZING MEASUREMENT TIME DELAY AS THE CHARACTERISTIC PARAMETER FOR LEVEL DEFINITION - A computer program product for operating a memory cell and memory array. The computer program product of memory cell operation entails receiving a request to read a binary value stored in the memory cell. A pre-charging operation pre-charges a bit-line capacitor in an electronic circuit formed by the memory cell to a pre-charge voltage. A word-line in the electronic circuit is then activated. A discharging operation discharges the bit-line capacitor through the said memory cell in the electronic circuit to the word-line. Additionally, an electron discharge time measurement is started when the word-line is activated. The electron discharge time measurement is stopped when the voltage level in the bit-line falls below a pre-defined reference voltage. A determining operation determines the binary value from the measured electron discharge time.06-03-2010
20100176362POLYSILICON PLUG BIPOLAR TRANSISTOR FOR PHASE CHANGE MEMORY - Memory devices and methods for manufacturing are described herein. A memory device described herein includes a plurality of memory cells. Memory cells in the plurality of memory cells comprise respective bipolar junction transistors and memory elements. The bipolar junction transistors are arranged in a common collector configuration and include an emitter comprising doped polysilicon having a first conductivity type, the emitter contacting a corresponding word line in a plurality of word lines to define a pn junction. The bipolar junction transistors include a portion of the corresponding word line underlying the emitter acting as a base, and a collector comprising a portion of the single-crystalline substrate underlying the base.07-15-2010
20100181649POLYSILICON PILLAR BIPOLAR TRANSISTOR WITH SELF-ALIGNED MEMORY ELEMENT - Memory cells having memory elements self-aligned with the emitters of bipolar junction transistor access devices are described herein, as well as methods for manufacturing such devices. A memory device as described herein comprises a plurality of memory cells. Memory cells in the plurality of memory cells include a bipolar junction transistor comprising an emitter comprising a pillar of doped polysilicon. The memory cells include an insulating element over the emitter and having an opening extending through the insulating layer, the opening centered over the emitter. The memory cells also include a memory element within the opening and electrically coupled to the emitter.07-22-2010
20100214811CODING TECHNIQUES FOR IMPROVING THE SENSE MARGIN IN CONTENT ADDRESSABLE MEMORIES - A content addressable memory using encoded data words and search words, and techniques for operating such device. In one embodiment, the data word is transformed into a code word guaranteeing a mismatch of at least two code word bits of different binary values during the memory search operation when the data word does not match a search word. In another embodiment, the search word is transformed into a search code such that the Hamming distance between the code word and the search code is greater than a given threshold when there is a mismatch of at least one bit between the data word and the search word.08-26-2010
20100226161TERNARY CONTENT ADDRESSABLE MEMORY USING PHASE CHANGE DEVICES - A content addressable memory device with a plurality of memory cells storing ternary data values of high, low, and don't care. An aspect of the content addressable memory device is the use of first memory elements and second memory elements in the memory cells. The first and second memory elements are electrically coupled in parallel circuit to a match-line. The first memory elements are coupled to first word-lines and the second memory elements are coupled to second word-lines. The first memory elements are configured to store low resistance states if the ternary data value is low and high resistance states if the ternary data value is either high or don't care. The second memory elements are configured to store the low resistance states if the ternary data value is high and the high resistance states if the ternary data value is either low or don't care.09-09-2010
20100265748HIGH DENSITY TERNARY CONTENT ADDRESSABLE MEMORY - A content addressable memory device with a plurality of memory cells storing data words. Each data bit in the data words is set to one of three values of a first binary value, a second binary value, and a don't care value. An aspect of the content addressable memory device is the use of a single memory element and an access device in the memory cells. The memory cells are arranged such that each memory cell is electrically coupled to a single bit line, a single match line, and a single word line. The memory elements in the memory cells store low resistance states if the data bit value is the first binary value, high resistance states if the data bit value is the second binary value, and very high resistance states if the data bit value is the don't care value.10-21-2010
20100295009Phase Change Memory Cells Having Vertical Channel Access Transistor and Memory Plane - Memory devices are described along with methods for manufacturing. A memory device as described herein comprises a plurality of word lines overlying a plurality of bit lines, and a plurality of field effect transistors. Field effect transistors in the plurality of field effect transistors comprises a first terminal electrically coupled to a corresponding bit line in the plurality of bit lines, a second terminal overlying the first terminal, and a channel region separating the first and second terminals and adjacent a corresponding word line in the plurality of word lines. The corresponding word line acts as the gate of the field effect transistor. A dielectric separates the corresponding word line from the channel region. A memory plane comprises programmable resistance memory material electrically coupled to respective second terminals of the field effect transistors, and conductive material on the programmable resistance memory material and coupled to a common voltage.11-25-2010
20100328994PHASE CHANGE MEMORY WITH FINITE ANNULAR CONDUCTIVE PATH - A phase change memory device and a method for programming the same. The method includes determining a maximum possible resistance for the memory cells in the phase change memory device. The method includes determining a high resistance state for the memory cells in the phase change memory device. The method includes receiving a request to program a target memory cell in the phase change memory device to the high resistance state. The method also includes resetting the target memory cell in the phase change memory device to the high resistance state such that the high resistance state of the target memory cell is of less resistance than the maximum possible resistance. In one embodiment of the invention, the high resistance state for the memory cells in the phase change memory device is at least 10% less than the maximum possible resistance.12-30-2010