Patents Assigned to Sandisk 3D LLC
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Patent number: 8298931Abstract: A method for fabricating a 3-D monolithic memory device in which a via and trench are etched using an amorphous carbon hard mask. The via extends in multiple levels of the device as a multi-level vertical interconnect. The trench extends laterally, such as to provide a word line or bit line for memory cells, or to provide other routing paths. A dual damascene process can be used in which the via is formed first and the trench is formed second, or the trench is formed first and the via is formed second. The technique is particularly suitable for deep via applications, such as for via depths of greater than 1 ?m. A dielectric antireflective coating, optionally with a bottom antireflective coating, can be used to etch an amorphous carbon layer to provide the amorphous carbon hard mask.Type: GrantFiled: September 28, 2007Date of Patent: October 30, 2012Assignee: SanDisk 3D LLCInventors: Usha Raghuram, Michael W. Konevecki
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Patent number: 8289749Abstract: A method and system for forming reversible resistivity-switching elements is described herein. Forming refers to reducing the resistance of the reversible resistivity-switching element, and is generally understood to refer to reducing the resistance for the first time. Prior to forming the reversible resistivity-switching element it may be in a high-resistance state. A first voltage is applied to “partially form” the reversible resistivity-switching element. The first voltage has a first polarity. Partially forming the reversible resistivity-switching element lowers the resistance of the reversible resistivity-switching element. A second voltage that has the opposite polarity as the first is then applied to the reversible resistivity-switching element. Application of the second voltage may further lower the resistance of the reversible resistivity-switching element. Therefore, the second voltage could be considered as completing the forming of the reversible resistivity-switching element.Type: GrantFiled: December 18, 2009Date of Patent: October 16, 2012Assignee: SanDisk 3D LLCInventors: Xiying Chen, Abhijit Bandyopadhyay, Brian Le, Roy Scheuerlein, Li Xiao
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Patent number: 8284589Abstract: A memory device includes diode plus resistivity switching element memory cells coupled between bit and word lines, single device bit line drivers with gates coupled to a bit line decoder control lead, sources/drains coupled to a bit line driver, and drains/sources coupled to bit lines, single device word line drivers with gates coupled to a word line decoder control lead, sources/drains coupled to a word line driver output, and drains/sources coupled to word lines, a first bleeder diode coupled between a bit line and a first bleeder diode controller, and a second bleeder diode coupled between a word line and a second bleeder diode controller. The first bleeder diode controller connects the first bleeder diode to low voltage in response to a bit line decoder signal. The second bleeder diode controller connects the second bleeder diode to high voltage in response to a word line decoder signal.Type: GrantFiled: November 2, 2010Date of Patent: October 9, 2012Assignee: SanDisk 3D LLCInventor: Roy E. Scheuerlein
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Patent number: 8283706Abstract: A die is formed with different and optimized critical dimensions in different device levels and areas of those device levels using photolithography and etch techniques. One aspect of the invention provides for a memory array formed above a substrate, with driver circuitry formed in the substrate. A level of the memory array consists of, for example, parallel rails and a fan-out region. It is desirable to maximize density of the rails and minimize cost of lithography for the entire memory array. This can be achieved by forming the rails at a tighter pitch than the CMOS circuitry beneath it, allowing cheaper lithography tools to be used when forming the CMOS, and similarly by optimizing lithography and etch techniques for a device level to produce a tight pitch in the rails, and a more relaxed pitch in the less-critical fan-out region.Type: GrantFiled: June 10, 2008Date of Patent: October 9, 2012Assignee: SanDisk 3D LLCInventors: James M. Cleeves, Roy E. Scheuerlein
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Patent number: 8279650Abstract: A storage system includes a three-dimensional memory array that has multiple layers of non-volatile storage elements grouped into blocks. Each block includes a subset of first selection circuits for selectively coupling a subset of array lines (e.g. bit lines) of a first type to respective local data lines. Each block includes a subset of second selection circuits for selectively coupling a subset of the respective local data lines to global data lines that are connected to control circuitry. To increase the performance of memory operations, the second selections circuits can change their selections independently of each other. For example, a memory operation is performed concurrently on a first non-volatile storage element of each group of a plurality of groups of non-volatile storage elements. Completion of the memory operation for the first non-volatile storage element of each group is independently detected.Type: GrantFiled: September 20, 2009Date of Patent: October 2, 2012Assignee: SanDisk 3D LLCInventors: Tianhong Yan, Luca Fasoli
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Patent number: 8279704Abstract: Circuits and methods are described for decoding exemplary memory arrays of programmable and, in some embodiments, re-writable passive element memory cells, which are particularly useful for extremely dense three-dimensional memory arrays having more than one memory plane. In addition, circuits and methods are described for selecting one or more array blocks of such a memory array, for selecting one or more word lines and bit lines within selected array blocks, for conveying data information to and from selected memory cells within selected array blocks, and for conveying unselected bias conditions to unselected array blocks.Type: GrantFiled: September 30, 2010Date of Patent: October 2, 2012Assignee: SanDisk 3D LLCInventors: Roy E. Scheuerlein, Luca G. Fasoli
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Patent number: 8274130Abstract: A storage system and method for forming a storage system that uses punch-through diodes as a steering element in series with a reversible resistivity-switching element is described. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. Therefore, it is compatible with bipolar switching in cross-point memory arrays having resistive switching elements. The punch-through diode may be a N+/P?/N+ device or a P+/N?/P+ device.Type: GrantFiled: October 20, 2009Date of Patent: September 25, 2012Assignee: SanDisk 3D LLCInventors: Andrei Mihnea, Deepak C. Sekar, George Samachisa, Roy Scheuerlein, Li Xiao
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Patent number: 8275927Abstract: Methods and apparatus are provided for a solid state non-volatile storage sub-system of a computer. The storage sub-system includes a write-once storage sub-system memory device and a write-many storage sub-system memory device. The write-once storage sub-system memory device includes a recoverable system configuration. Numerous other aspects are provided.Type: GrantFiled: December 31, 2007Date of Patent: September 25, 2012Assignee: SanDisk 3D LLCInventors: Roy E. Scheuerlein, Randhir Thakur, Christopher Moore
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Publication number: 20120236624Abstract: Improved methods for programming multi-level metal oxide memory cells balance applied voltage and current to provide improved performance. Set programming, which transitions the memory cell to a lower resistance state, is accomplished by determining an appropriate programming voltage and current limit for the objective resistance state to be achieved in the programming and then applying a pulse having the determined set electrical characteristics. Reset programming, which transitions the memory cell to a higher resistance state, is accomplished by determining an appropriate programming voltage and optionally current limit for the state to be achieved in the programming and then applying a pulse having the determined electrical characteristics. The algorithm used to determine the appropriate set or reset programming voltage and current values provides for effective programming without stressing the memory element.Type: ApplicationFiled: March 18, 2011Publication date: September 20, 2012Applicant: SanDisk 3D LLCInventors: Xiying Costa, Yibo Nian, Roy Scheuerlein, Tz-Yi Liu, Chandrasekhar Reddy Gorla
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Patent number: 8270199Abstract: A memory system includes an X line, a first Y line, a second Y line, a semiconductor region of a first type running along the X line, first switching material and a first semiconductor region of a second type between the first Y line and the semiconductor region of the first type, second switching material and a second semiconductor region of the second type between the second Y line and the semiconductor region of the first type, and control circuitry. The control circuitry is in communication with the X line, the first Y line and the second Y line. The control circuitry changes the programming state of the first switching material to a first state by causing a first current to flow from the second Y line to the first Y line through the first switching material, the second switching material, the semiconductor region of the first type, the first semiconductor region of the second type and the second semiconductor region of the second type.Type: GrantFiled: April 3, 2009Date of Patent: September 18, 2012Assignee: SanDisk 3D LLCInventor: Roy E. Scheuerlein
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Patent number: 8268678Abstract: A method of making a non-volatile memory device includes providing a substrate having a substrate surface, and forming a non-volatile memory array over the substrate surface. The non-volatile memory array includes an array of semiconductor diodes, and each semiconductor diode of the array of semiconductor diodes is disposed substantially parallel to the substrate surface.Type: GrantFiled: November 18, 2010Date of Patent: September 18, 2012Assignee: SanDisk 3D LLCInventors: Steven Maxwell, Michael Konevecki, Mark H. Clark, Usha Raghuram
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Patent number: 8270202Abstract: Control circuitry provides control signals to a common X line and a set of Y lines to change a first data storage element of the multiple data storage elements from a first state to a second state by passing a current into the first data storage element from a different Y line through a different storage element. The control circuitry provides control signals to the common X line and the set of Y lines to sequentially change additional data storage elements of the multiple data storage elements from the first state to the second state by passing currents into the additional data storage elements from data storage elements of the multiple data storage elements that were previously changed to the second state and their associated different Y lines.Type: GrantFiled: June 7, 2011Date of Patent: September 18, 2012Assignee: SanDisk 3D, LLCInventor: Roy E. Scheuerlein
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Patent number: 8270210Abstract: A non-volatile storage system includes a substrate, control circuitry on the substrate, a three dimensional memory array (above the substrate) that includes a plurality of memory cells with reversible resistance-switching elements, and circuits to SET and RESET the resistance-switching elements. The circuits that RESET the resistance-switching elements provide a pulse to the memory cells that is large enough in magnitude to SET and RESET the memory cells, and long enough to potentially RESET the memory cell but not long enough to SET the memory cells.Type: GrantFiled: June 7, 2011Date of Patent: September 18, 2012Assignee: SanDisk 3D, LLCInventor: Roy E. Scheuerlein
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Patent number: 8263420Abstract: Optimized electrodes for ReRAM memory cells and methods for forming the same are discloses. One aspect comprises forming a first electrode, forming a state change element in contact with the first electrode, treating the state change element, and forming a second electrode. Treating the state change element increases the barrier height at the interface between the second electrode and the state change element. Another aspect comprises forming a first electrode in a manner to deliberately establish a certain degree of amorphization in the first electrode, forming a state change element in contact with the first electrode. The degree of amorphization of the first electrode is either at least as great as the degree of amorphization of the state change element or no more than 5 percent less than the degree of amorphization of the state change element.Type: GrantFiled: February 3, 2009Date of Patent: September 11, 2012Assignee: SanDisk 3D LLCInventors: Depak C. Sekar, April Schricker, Xiying Chen, Klaus Schuegraf, Raghuveer Makala
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Publication number: 20120223380Abstract: There is provided a monolithic three dimensional array of charge storage devices which includes a plurality of device levels, wherein at least one surface between two successive device levels is planarized by chemical mechanical polishing.Type: ApplicationFiled: May 10, 2012Publication date: September 6, 2012Applicant: SanDisk 3D LLCInventors: Thomas H. Lee, Vivek Subramanian, James M. Cleeves, Andrew J. Walker, Christopher J. Petti, Igor G. Kouznetzov, Mark G. Johnson, Paul Michael Farmwald, Brad Herner
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Patent number: 8252644Abstract: A method for forming a nonvolatile memory cell is provided that includes: (1) forming a rail-shaped first conductor above a substrate, (2) forming a rail-shaped second conductor above the first conductor, and (3) forming a substantially vertical first pillar disposed between the first conductor and the second conductor. The first pillar includes a vertically oriented p-i-n diode, and the p-i-n diode includes: (a) a bottom heavily doped region having a first conductivity type, (b) a middle intrinsic or lightly doped region, and (c) a top heavily doped region having a second conductivity type opposite the first conductivity type. The bottom heavily doped region is doped by implantation of arsenic ions and the top heavily doped region is doped by implantation of BF2 ions. Numerous additional aspects are provided.Type: GrantFiled: September 8, 2011Date of Patent: August 28, 2012Assignee: SanDisk 3D LLCInventors: Scott Brad Herner, Steven J. Radigan
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Patent number: 8241969Abstract: A method of making a device includes forming a first photoresist layer over a sacrificial layer, patterning the first photoresist layer to form first photoresist features, rendering the first photoresist features insoluble to a solvent, forming a second photoresist layer over the first photoresist features, patterning the second photoresist layer to form second photoresist features, forming a spacer layer over the first and second photoresist features, etching the spacer layer to form spacer features and to expose the first and second photoresist features, forming third photoresist features between the spacer features, removing the spacer features, and patterning the sacrificial layer using the first, second and third photoresist features as a mask to form sacrificial features.Type: GrantFiled: August 24, 2011Date of Patent: August 14, 2012Assignee: SanDisk 3D LLCInventors: Natalie Nguyen, Paul Wai Kie Poon, Steven J. Radigan, Michael Konevecki, Yung-Tin Chen, Raghuveer Makala, Vance Dunton
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Patent number: 8243509Abstract: A nonvolatile memory cell is described, the memory cell comprising a semiconductor diode. The semiconductor material making up the diode is formed with significant defect density, and allows very low current flow at a typical read voltage. Application of a programming voltage permanently changes the nature of the semiconductor material, resulting in an improved diode. The programmed diode allows much higher current flow, in some embodiments one, two or three orders of magnitude higher, at the same read voltage. The difference in current allows a programmed memory cell to be distinguished from an unprogrammed memory cell. Fabrication techniques to generate an advantageous unprogrammed defect density are described. The memory cell of the present invention can be formed in a monolithic three dimensional memory array, having multiple stacked memory levels formed above a single substrate.Type: GrantFiled: March 29, 2011Date of Patent: August 14, 2012Assignee: SanDisk 3D LLCInventors: S. Brad Herner, Abhijit Bandyopadhyay
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Patent number: 8238174Abstract: A non-volatile storage system connects a signal driver to a first control line that is connected to a first non-volatile storage element, charges the first control line using the signal driver while the signal driver is connected to the first control line, disconnects the signal driver from the first control line while the first control line remains charged from the signal driver, connects the signal driver to a second control line that is connected to a second non-volatile storage element, charges the second control line using the signal driver while the signal driver is connected to the second control line, and disconnects the signal driver from the second control line. Charging the control lines causes the respective non-volatile storage elements to experience a program operation.Type: GrantFiled: August 24, 2011Date of Patent: August 7, 2012Assignee: SanDisk 3D LLCInventors: Tianhong Yan, Luca Fasoli
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Patent number: 8236623Abstract: In some aspects, a method of fabricating a memory cell is provided that includes (1) fabricating a steering element above a substrate; and (2) fabricating a reversible-resistance switching element coupled to the steering element by selectively fabricating carbon nano-tube (CNT) material above the substrate. Numerous other aspects are provided.Type: GrantFiled: December 31, 2007Date of Patent: August 7, 2012Assignee: SanDisk 3D LLCInventors: April Schricker, Mark Clark, Brad Herner