Patents by Inventor Vidyut Gopal
Vidyut Gopal has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9543516Abstract: Methods for producing RRAM resistive switching elements having reduced forming voltage include doping to create oxygen deficiencies in the dielectric film. Oxygen deficiencies in a dielectric film promote formation of conductive pathways.Type: GrantFiled: June 27, 2014Date of Patent: January 10, 2017Assignees: Intermolecular, Inc., SanDisk 3D LLC, Kabushiki Kaisha ToshibaInventors: Jinhong Tong, Randall Higuchi, Imran Hashim, Vidyut Gopal
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Patent number: 9444047Abstract: Provided are nonvolatile memory assemblies each including a resistive switching layer and current steering element. The steering element may be a transistor connected in series with the switching layer. Resistance control provided by the steering element allows using switching layers requiring low switching voltages and currents. Memory assemblies including such switching layers are easier to embed into integrated circuit chips having other low voltage components, such as logic and digital signal processing components, than, for example, flash memory requiring much higher switching voltages. In some embodiments, provided nonvolatile memory assemblies operate at switching voltages less than about 3.0V and corresponding currents less than 50 microamperes. A memory element may include a metal rich hafnium oxide disposed between a titanium nitride electrode and doped polysilicon electrode. One electrode may be connected to a drain or source of the transistor, while another electrode is connected to a signal line.Type: GrantFiled: July 22, 2015Date of Patent: September 13, 2016Assignee: Intermolecular, Inc.Inventors: Imran Hashim, Tony P. Chiang, Vidyut Gopal, Yun Wang
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Publication number: 20160172588Abstract: Methods for producing RRAM resistive switching elements having reduced forming voltage include doping to create oxygen deficiencies in the dielectric film. Oxygen deficiencies in a dielectric film promote formation of conductive pathways.Type: ApplicationFiled: June 27, 2014Publication date: June 16, 2016Inventors: Jinhong Tong, Randall Higuchi, Imran Hashim, Vidyut Gopal
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Patent number: 9318333Abstract: In patterning a transistor, some of a layer of gate dielectric material is allowed to remain over a semiconductor substrate upon which the transistor is formed. This remaining dielectric material retards the implantation of dopants into the underlying substrate, effectively lengthening a channel region of the transistor. This mitigates unwanted short channel effects, such as leakage currents, for example, and thus mitigates yield loss by establishing a transistor that performs in a more predictable or otherwise desirable manner.Type: GrantFiled: March 16, 2007Date of Patent: April 19, 2016Assignee: CYPRESS SEMICONDUCTOR CORPORATIONInventors: Vidyut Gopal, Shankar Sinha, Jean Yee-Mei Yang, Phillip L. Jones
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Patent number: 9269896Abstract: Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A stack including a defect source layer, a defect blocking layer, and a defect acceptor layer disposed between the defect source layer and the defect blocking layer may be subjected to annealing. During the annealing, defects are transferred in a controllable manner from the defect source layer to the defect acceptor layer. At the same time, the defects are not transferred into the defect blocking layer thereby creating a lowest concentration zone within the defect acceptor layer. This zone is responsible for resistive switching. The precise control over the size of the zone and the defect concentration within the zone allows substantially improvement of resistive switching characteristics of the ReRAM cell. In some embodiments, the defect source layer includes aluminum oxynitride, the defect blocking layer includes titanium nitride, and the defect acceptor layer includes aluminum oxide.Type: GrantFiled: October 21, 2014Date of Patent: February 23, 2016Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Yun Wang, Vidyut Gopal, Chien-Lan Hsueh
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Patent number: 9246096Abstract: Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.Type: GrantFiled: February 17, 2015Date of Patent: January 26, 2016Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Zhendong Hong, Vidyut Gopal, Imran Hashim, Randall J. Higuchi, Tim Minvielle, Hieu Pham, Takeshi Yamaguchi
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Publication number: 20150325788Abstract: Provided are nonvolatile memory assemblies each including a resistive switching layer and current steering element. The steering element may be a transistor connected in series with the switching layer. Resistance control provided by the steering element allows using switching layers requiring low switching voltages and currents. Memory assemblies including such switching layers are easier to embed into integrated circuit chips having other low voltage components, such as logic and digital signal processing components, than, for example, flash memory requiring much higher switching voltages. In some embodiments, provided nonvolatile memory assemblies operate at switching voltages less than about 3.0V and corresponding currents less than 50 microamperes. A memory element may include a metal rich hafnium oxide disposed between a titanium nitride electrode and doped polysilicon electrode. One electrode may be connected to a drain or source of the transistor, while another electrode is connected to a signal line.Type: ApplicationFiled: July 22, 2015Publication date: November 12, 2015Inventors: Imran Hashim, Tony P. Chiang, Vidyut Gopal, Yun Wang
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Patent number: 9130165Abstract: Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies.Type: GrantFiled: October 3, 2014Date of Patent: September 8, 2015Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Yun Wang, Tony P. Chiang, Vidyut Gopal, Imran Hashim, Dipankar Pramanik
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Patent number: 9129894Abstract: Provided are nonvolatile memory assemblies each including a resistive switching layer and current steering element. The steering element may be a transistor connected in series with the switching layer. Resistance control provided by the steering element allows using switching layers requiring low switching voltages and currents. Memory assemblies including such switching layers are easier to embed into integrated circuit chips having other low voltage components, such as logic and digital signal processing components, than, for example, flash memory requiring much higher switching voltages. In some embodiments, provided nonvolatile memory assemblies operate at switching voltages less than about 3.0V and corresponding currents less than 50 microamperes. A memory element may include a metal rich hafnium oxide disposed between a titanium nitride electrode and doped polysilicon electrode. One electrode may be connected to a drain or source of the transistor, while another electrode is connected to a signal line.Type: GrantFiled: September 17, 2012Date of Patent: September 8, 2015Assignee: Intermolecular, Inc.Inventors: Imran Hashim, Tony Chiang, Vidyut Gopal, Yun Wang
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Patent number: 9087978Abstract: Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 ? and about 100 ?, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.Type: GrantFiled: February 10, 2015Date of Patent: July 21, 2015Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang
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Publication number: 20150200361Abstract: Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 ? and about 100 ?, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.Type: ApplicationFiled: February 10, 2015Publication date: July 16, 2015Inventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang
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Publication number: 20150188039Abstract: Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. The ReRAM cells may include a first layer operable as a bottom electrode and a second layer operable to switch between at least a first resistive state and a second resistive state. The ReRAM cells may include a third layer including a first oxygen getter material and a fourth layer including a metal silicon nitride. The ReRAM cells may further include a fifth layer including a second oxygen getter material. The first oxygen getter material and the second oxygen getter material may be more reactive with oxygen than the metal silicon nitride. A work function of the first oxygen getter material and a work function of the second oxygen getter material may be substantially lower than a work function of the metal silicon nitride. The ReRAM cells may include a sixth layer operable as a top electrode.Type: ApplicationFiled: December 26, 2013Publication date: July 2, 2015Applicant: Intermolecular Inc.Inventors: Yun Wang, Vidyut Gopal, Mihir Tendulkar
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Publication number: 20150179935Abstract: Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.Type: ApplicationFiled: February 17, 2015Publication date: June 25, 2015Inventors: Zhendong Hong, Vidyut Gopal, Imran Hashim, Randall J. Higuchi, Tim Minvielle, Hieu Pham, Takeshi Yamaguchi
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Patent number: 9065040Abstract: A method of fabricating a resistive random access memory (ReRAM) cell may include forming a set of nanolaminate structures over an electrode, such that each structure includes at least one first element oxide layer and at least one second element oxide layer. The overall set is operable as a resistive switching layer in a ReRAM cell. In this set, an average atomic ratio of the first element to the second element is different in at least two nanolaminate structures. This ratio may be less in nanolaminate structures that are closer to electrodes than in the middle nanolaminate structures. Alternatively, this ratio may increase from one end of the set to another. The first element may be less electronegative than the second elements. The first element may be hafnium, while the second element may be one of zirconium, aluminum, titanium, tantalum, or silicon.Type: GrantFiled: October 9, 2014Date of Patent: June 23, 2015Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Chien-Lan Hsueh, Vidyut Gopal, Randall J. Higuchi, Takeshi Yamaguchi
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Patent number: 9006026Abstract: Embodiments of the invention generally relate to nonvolatile memory devices and methods for manufacturing such memory devices. The methods for forming improved memory devices, such as a ReRAM cells, provide optimized, atomic layer deposition (ALD) processes for forming a metal oxide film stack which contains at least one hard metal oxide film (e.g., metal is completely oxidized or substantially oxidized) and at least one soft metal oxide film (e.g., metal is less oxidized than hard metal oxide). The soft metal oxide film is less electrically resistive than the hard metal oxide film since the soft metal oxide film is less oxidized or more metallic than the hard metal oxide film. In one example, the hard metal oxide film is formed by an ALD process utilizing ozone as the oxidizing agent while the soft metal oxide film is formed by another ALD process utilizing water vapor as the oxidizing agent.Type: GrantFiled: August 22, 2014Date of Patent: April 14, 2015Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Zhendong Hong, Vidyut Gopal, Imran Hashim, Randall J. Higuchi, Tim Minvielle, Hieu Pham, Takeshi Yamaguchi
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Patent number: 8987697Abstract: Embodiments of the invention include nonvolatile memory elements and memory devices comprising the nonvolatile memory elements. Methods for forming the nonvolatile memory elements are also disclosed. The nonvolatile memory element comprises a first electrode layer, a second electrode layer, and a plurality of layers of an oxide disposed between the first and second electrode layers. One of the oxide layers has linear resistance and substoichiometric composition, and the other oxide layer has bistable resistance and near-stoichiometric composition. Preferably, the sum of the two oxide layer thicknesses is between about 20 ? and about 100 ?, and the oxide layer with bistable resistance has a thickness between about 25% and about 75% of the total thickness. In one embodiment, the oxide layers are formed using reactive sputtering in an atmosphere with controlled flows of argon and oxygen.Type: GrantFiled: April 14, 2014Date of Patent: March 24, 2015Assignees: Intermolecular, Inc., Kabushiki Kaisha Toshiba, SanDisk 3D LLCInventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang
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Publication number: 20150060753Abstract: A method of fabricating a resistive random access memory (ReRAM) cell may include forming a set of nanolaminate structures over an electrode, such that each structure includes at least one first element oxide layer and at least one second element oxide layer. The overall set is operable as a resistive switching layer in a ReRAM cell. In this set, an average atomic ratio of the first element to the second element is different in at least two nanolaminate structures. This ratio may be less in nanolaminate structures that are closer to electrodes than in the middle nanolaminate structures. Alternatively, this ratio may increase from one end of the set to another. The first element may be less electronegative than the second elements. The first element may be hafnium, while the second element may be one of zirconium, aluminum, titanium, tantalum, or silicon.Type: ApplicationFiled: October 9, 2014Publication date: March 5, 2015Inventors: Chien-Lan Hsueh, Vidyut Gopal, Randall J. Higuchi, Takeshi Yamaguchi
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Publication number: 20150056749Abstract: Embodiments of the invention generally relate to nonvolatile memory devices, such as a ReRAM cells, and methods for manufacturing such memory devices, which includes optimized, atomic layer deposition (ALD) processes for forming metal oxide film stacks. The metal oxide film stacks contain a metal oxide coupling layer disposed on a metal oxide host layer, each layer having different grain structures/sizes. The interface disposed between the metal oxide layers facilitates oxygen vacancy movement. In many examples, the interface is a misaligned grain interface containing numerous grain boundaries extending parallel to the electrode interfaces, in contrast to the grains in the bulk film extending perpendicular to the electrode interfaces. As a result, oxygen vacancies are trapped and released during switching without significant loss of vacancies.Type: ApplicationFiled: October 3, 2014Publication date: February 26, 2015Inventors: Yun Wang, Tony P. Chiang, Vidyut Gopal, Imran Hashim, Dipankar Pramanik
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Publication number: 20150034898Abstract: Provided are resistive random access memory (ReRAM) cells and methods of fabricating thereof. A stack including a defect source layer, a defect blocking layer, and a defect acceptor layer disposed between the defect source layer and the defect blocking layer may be subjected to annealing. During the annealing, defects are transferred in a controllable manner from the defect source layer to the defect acceptor layer. At the same time, the defects are not transferred into the defect blocking layer thereby creating a lowest concentration zone within the defect acceptor layer. This zone is responsible for resistive switching. The precise control over the size of the zone and the defect concentration within the zone allows substantially improvement of resistive switching characteristics of the ReRAM cell. In some embodiments, the defect source layer includes aluminum oxynitride, the defect blocking layer includes titanium nitride, and the defect acceptor layer includes aluminum oxide.Type: ApplicationFiled: October 21, 2014Publication date: February 5, 2015Inventors: Yun Wang, Vidyut Gopal, Chien-Lan Hsueh
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Publication number: 20140374240Abstract: A nonvolatile memory element is disclosed comprising a first electrode, a near-stoichiometric metal oxide memory layer having bistable resistance, and a second electrode in contact with the near-stoichiometric metal oxide memory layer. At least one electrode is a resistive electrode comprising a sub-stoichiometric transition metal nitride or oxynitride, and has a resistivity between 0.1 and 10? cm. The resistive electrode provides the functionality of an embedded current-limiting resistor and also serves as a source and sink of oxygen vacancies for setting and resetting the resistance state of the metal oxide layer. Novel fabrication methods for the second electrode are also disclosed.Type: ApplicationFiled: September 8, 2014Publication date: December 25, 2014Inventors: Hieu Pham, Vidyut Gopal, Imran Hashim, Tim Minvielle, Dipankar Pramanik, Yun Wang, Takeshi Yamaguchi, Hong Sheng Yang