Patents Assigned to Sandisk 3D LLC
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Publication number: 20140175355Abstract: Provided are carbon doped resistive switching layers, resistive random access memory (ReRAM) cells including these layers, as well as methods of forming thereof. Carbon doping of metal containing materials creates defects in these materials that allow forming and breaking conductive paths as evidenced by resistive switching. Relative to many conventional dopants, carbon has a lower diffusivity in many suitable base materials. As such, these carbon doped materials exhibit structural stability and consistent resistive switching over many operating cycles. Resistive switching layers may include as much as 30 atomic percent of carbon, making the dopant control relatively simple and flexible. Furthermore, carbon doping has acceptor characteristics resulting in a high resistivity and low switching currents, which are very desirable for ReRAM applications. Carbon doped metal containing layer may be formed from metalorganic precursors at temperatures below saturation ranges of atomic layer deposition.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Yun Wang, Tony P. Chiang, Tim Minvielle, Takeshi Yamaguchi
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Publication number: 20140175356Abstract: Provided are resistive random access memory (ReRAM) cells including resistive switching layers and thermally isolating structures for limiting heat dissipation from the switching layers during operation. Thermally isolating structures may be positioned within a stack or adjacent to the stack. For example, a stack may include one or two thermally isolating structures. A thermally isolating structure may directly interface with a switching layer or may be separated by, for example, an electrode. Thermally isolating structures may be formed from materials having a thermal conductivity of less than 1 W/m*K, such as porous silica and mesoporous titanium oxide. A thermally isolating structure positioned in series with a switching layer generally has a resistance less than the low resistance state of the switching layer. A thermally isolating structure positioned adjacent to a switching layer may have a resistance greater than the high resistance state of the switching layer.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicants: Intermolecular Inc., SanDisk 3D LLC, Kabushiki Kaisha ToshibaInventors: Yun Wang, Tony P. Chiang, Tim Minvielle, Takeshi Yamaguchi
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Publication number: 20140175363Abstract: Provided are methods of forming nonvolatile memory elements including resistance switching layers. A method involves diffusing oxygen from a precursor layer to one or more reactive electrodes by annealing. At least one electrode in a memory element is reactive, while another may be inert. The precursor layer is converted into a resistance switching layer as a result of this diffusion. The precursor layer may initially include a stoichiometric oxide that generally does not exhibit resistance switching characteristics until oxygen vacancies are created. Metals forming such oxides may be more electronegative than metals forming a reactive electrode. The reactive electrode may have substantially no oxygen at least prior to annealing. Annealing may be performed at 250-400° C. in the presence of hydrogen. These methods simplify process control and may be used to form nonvolatile memory elements including resistance switching layers less than 20 Angstroms thick.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Mihir Tendulkar, Tim Minvielle, Yun Wang, Takeshi Yamaguchi
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Publication number: 20140175362Abstract: Provided are ReRAM cells, each having at least one interface between an electrode and a resistive switching layers with a maximum field value of less than 0.25. The electrode materials forming such interfaces include tantalum nitrides doped with lanthanum, aluminum, erbium yttrium, or terbium (e.g., TaX(Dopant)YN, where X is at least about 0.95). The electrode materials have low work functions (e.g., less than about 4.5 eV). At the same time, the resistive switching materials have high relative dielectric permittivities (e.g., greater than about 30) and high electron affinities (greater than about for 3.5 eV). Niobium oxide is one example of a suitable resistive switching material. Another electrode interfacing the resistive switching layer may have different characteristics and, in some embodiments, may be an inert electrode.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Intermolecular Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
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Publication number: 20140179068Abstract: A three-dimensional array read/write (R/W) memory elements is formed across multiple layers of planes positioned at different distances above a semiconductor substrate. It is preferable to operate the R/W elements with low current and high resistive states. The resistance of these resistive states depends also on the dimension of the R/W elements and is predetermined by the process technology. A sheet electrode in series with the R/W element and a method of forming it provide another degree of freedom to adjust the resistance of the R/W memory element. The thickness of the sheet electrode is adjusted to obtain a reduced cross-sectional contact in the circuit path from the word line to the bit line. This allows the R/W memory element to have a much increased resistance and therefore to operate with much reduced currents. The sheet electrode is formed with little increase in cell size.Type: ApplicationFiled: January 7, 2014Publication date: June 26, 2014Applicant: SanDisk 3D LLCInventors: George Samachisa, Johann Alsmeier
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Publication number: 20140175364Abstract: Provided are radiation enhanced resistive switching layers, resistive random access memory (ReRAM) cells including these layers, as well as methods of forming these layers and cells. Radiation creates defects in resistive switching materials that allow forming and breaking conductive paths in these materials thereby improving their resistive switching characteristics. For example, ionizing radiation may break chemical bonds in various materials used for such a layer, while non-ionizing radiation may form electronic traps. Radiation power, dozing, and other processing characteristics can be controlled to generate a distribution of defects within the resistive switching layer. For example, an uneven distribution of defects through the thickness of a layer may help with lowering switching voltages and/or currents. Radiation may be performed before or after thermal annealing, which may be used to control distribution of radiation created defects and other types of defects in resistive switching layers.Type: ApplicationFiled: December 20, 2012Publication date: June 26, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Intermolecular Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
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Patent number: 8759176Abstract: Methods in accordance with the invention involve patterning and etching very small dimension pillars, such as in formation of a memory array in accordance with the invention. When dimensions of pillars become very small, the photoresist pillars used to pattern them may not have sufficient mechanical strength to survive the photoresist exposure and development process. Using methods according to the present invention, these photoresist pillars are printed and developed larger than their intended final dimension, such that they have increased mechanical strength, then are shrunk to the desired dimension during a preliminary etch performed before the etch of underlying material begins.Type: GrantFiled: April 10, 2009Date of Patent: June 24, 2014Assignee: SanDisk 3D LLCInventors: Usha Raghuram, Michael W. Konevecki
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Publication number: 20140166960Abstract: A nonvolatile memory device that contains a resistive switching memory element with improved device switching performance and lifetime, and methods of forming the same. A nonvolatile memory element includes a first electrode layer formed on a substrate, a resistive switching layer formed on the first electrode layer, and a second electrode layer. The resistive switching layer comprises a metal oxide and is disposed between the first electrode layer and the second electrode layer. The elemental metal selected for each of the first and second electrode layers is the same metal as selected to form the metal oxide resistive switching layer. The use of common metal materials within the memory element eliminates the growth of unwanted and incompatible native oxide interfacial layers that create undesirable circuit impedance.Type: ApplicationFiled: December 13, 2012Publication date: June 19, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Intermolecular Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLC
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Publication number: 20140166968Abstract: A nonvolatile memory cell is provided that includes a diode and a reversible resistance-switching element that includes a resistance-switching metal oxide or nitride, the metal oxide or nitride including only one metal. Numerous other aspects are provided.Type: ApplicationFiled: February 19, 2014Publication date: June 19, 2014Applicant: SANDISK 3D LLCInventors: Scott Brad Herner, Christopher J. Petti, Tanmay Kumar
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Publication number: 20140166969Abstract: Embodiments of the invention generally include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has improved device switching performance and lifetime, due to the addition of a current limiting component disposed therein. The electrical properties of the current limiting component are configured to lower the current flow through the variable resistance layer during the logic state programming steps by adding a fixed series resistance in the resistive switching memory element of the nonvolatile memory device. In one embodiment, the current limiting component comprises a tunnel oxide that is a current limiting material disposed within a resistive switching memory element in a nonvolatile resistive switching memory device.Type: ApplicationFiled: February 19, 2014Publication date: June 19, 2014Applicants: Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Mihir Tendulkar, Imran Hashim, Yun Wang
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Publication number: 20140170847Abstract: Techniques disclosed herein may achieve crack free filling of structures. A flowable film may substantially fill gaps in a structure and extend over a base in an open area adjacent to the structure. The top surface of the flowable film in the open area may slope down and may be lower than top surfaces of the structure. A capping layer having compressive stress may be formed over the flowable film. The bottom surface of the capping layer in the open area adjacent to the structure is lower than the top surfaces of the lines and may be formed on the downward slope of the flowable film. The flowable film is cured after forming the capping layer, which increases tensile stress of the flowable film. The compressive stress of the capping layer counteracts the tensile stress of the flowable film, which may prevent a crack from forming in the base.Type: ApplicationFiled: January 15, 2013Publication date: June 19, 2014Applicant: SANDISK 3D LLCInventors: Hiroaki Iuchi, Hitomi Fujimoto, Chao Feng Yeh
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Publication number: 20140166956Abstract: A nonvolatile memory device contains a resistive switching memory element with improved device switching performance and lifetime by custom tailoring the average concentration of defects in the resistive switching film and methods of forming the same. The nonvolatile memory element includes a first electrode layer, a second electrode layer, and a resistive switching layer disposed between the first electrode layer and the second electrode layer. The resistive switching layer comprises a first sub-layer and a second sub-layer, wherein the first sub-layer has more defects than the first sub-layer. A method includes forming a first sub-layer on the first electrode layer by a first ALD process and forming a second sub-layer on the first sub-layer by a second ALD process, where the first sub-layer has a different amount of defects than the second sub-layer.Type: ApplicationFiled: December 13, 2012Publication date: June 19, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Randall J. Higuchi, Chien-Lan Hsueh, Yun Wang
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Patent number: 8755223Abstract: A three-dimensional array adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. Bit lines to which the memory elements of all planes are connected are oriented vertically from the substrate and through the plurality of planes.Type: GrantFiled: December 12, 2011Date of Patent: June 17, 2014Assignee: Sandisk 3D LLCInventor: Roy E. Scheuerlein
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Publication number: 20140158974Abstract: A memory cell is provided that includes a diode and a resistance-switching material layer coupled in series with the diode. The resistance-switching material layer has a thickness between 20 and 65 angstroms. Other aspects are also provided.Type: ApplicationFiled: February 14, 2014Publication date: June 12, 2014Applicant: SanDisk 3D LLCInventors: Xiaoyu Yang, Roy E. Scheuerlein, Feng Li, Albert T. Meeks
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Publication number: 20140158975Abstract: A method of forming a memory cell is provided. The method includes forming a steering element pillar having a first stiffness and a sidewall, forming a sidewall collar along at least a portion of the sidewall of the steering element pillar, the sidewall collar having a second stiffness, wherein the second stiffness is greater than the first stiffness, and forming a memory element coupled to the steering element pillar. Numerous other aspects are provided.Type: ApplicationFiled: February 17, 2014Publication date: June 12, 2014Applicant: SanDisk 3D LLCInventor: Scott Brad Herner
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Patent number: 8748237Abstract: A resistor structure incorporated into a resistive switching memory cell or device to form memory devices with improved device performance and lifetime is provided. The resistor structure may be a two-terminal structure designed to reduce the maximum current flowing through a memory device. A method is also provided for making such memory device. The method includes depositing a resistor structure and depositing a variable resistance layer of a resistive switching memory cell of the memory device, where the resistor structure is disposed in series with the variable resistance layer to limit the switching current of the memory device. The incorporation of the resistor structure is very useful in obtaining desirable levels of device switching currents that meet the switching specification of various types of memory devices. The memory devices may be formed as part of a high-capacity nonvolatile memory integrated circuit, which can be used in various electronic devices.Type: GrantFiled: October 28, 2013Date of Patent: June 10, 2014Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Dipankar Pramanik, Tony P. Chiang, Mankoo Lee
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Patent number: 8750066Abstract: Methods for operating a semiconductor memory array including dynamically adjusting control line voltages (e.g., unselected word line or unselected bit line voltages) based on one or more array conditions associated with the semiconductor memory array are described. The one or more array conditions may include a temperature associated with the semiconductor memory array or a particular number of write cycles associated with the semiconductor memory array. In some embodiments, an intermediate voltage is generated based on the one or more array conditions and applied to the unselected word lines and the unselected bit lines of the semiconductor memory array. The one or more intermediate voltages may be generated such that a first voltage difference across unselected memory cells sharing a selected word line is different from a second voltage difference across other unselected memory cells sharing a selected bit line based on the one or more array conditions.Type: GrantFiled: October 2, 2013Date of Patent: June 10, 2014Assignee: Sandisk 3D LLCInventors: Roy E. Scheuerlein, George Samachisa
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Patent number: 8748859Abstract: An integrated circuit including vertically oriented diode structures between conductors and methods of fabricating the same are provided. Two-terminal devices such as passive element memory cells can include a diode steering element in series with an antifuse and/or other state change element. The devices are formed using pillar structures at the intersections of upper and lower sets of conductors. The height of the pillar structures are reduced by forming part of the diode for each pillar in a rail stack with one of the conductors. A diode in one embodiment can include a first diode component of a first conductivity type and a second diode component of a second conductivity type. A portion of one of the diode components is divided into first and second portions with one on the portions being formed in the rail stack where it is shared with other diodes formed using pillars at the rail stack.Type: GrantFiled: April 6, 2012Date of Patent: June 10, 2014Assignee: SanDisk 3D LLCInventors: Kang-Jay Hsia, Christopher J Petti, Calvin K Li
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Publication number: 20140151621Abstract: Embodiments of the invention include a nonvolatile memory device that contains nonvolatile resistive random access memory device with improved device performance and lifetime. In some embodiments, nonvolatile resistive random access memory device includes a diode, a metal silicon nitride embedded resistor, and a resistive switching layer disposed between a first electrode layer and a second electrode layer. In some embodiments, the method of forming a resistive random access memory device includes forming a diode, forming a metal silicon nitride embedded resistor, forming a first electrode layer, forming a second electrode layer, and forming a resistive switching layer disposed between the first electrode layer and the second electrode layer.Type: ApplicationFiled: December 3, 2012Publication date: June 5, 2014Applicants: INTERMOLECULAR INC., SANDISK 3D LLC, KABUSHIKI KAISHA TOSHIBAInventors: Mihir Tendulkar, David Chi
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Publication number: 20140151625Abstract: Embodiments of the invention include a method of forming a nonvolatile memory device that contains a resistive switching memory element that has improved device switching performance and lifetime, due to the addition of a current limiting component disposed therein. The electrical properties of the current limiting component are configured to lower the current flow through the variable resistance layer during the logic state programming steps by adding a fixed series resistance in the resistive switching memory element of the nonvolatile memory device. In some embodiments, the current limiting component comprises a varistor that is a current limiting material disposed within a resistive switching memory element in a nonvolatile resistive switching memory device.Type: ApplicationFiled: February 10, 2014Publication date: June 5, 2014Applicants: Kabushiki Kaisha Toshiba, SANDISK 3D LLCInventors: Mihir Tendulkar, Imran Hashim, Yun Wang