Patents by Inventor Rajiv Yadav Ranjan
Rajiv Yadav Ranjan 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: 9081669Abstract: A hybrid non-volatile memory device includes a non-volatile random access memory (NVRAM) having an array of magnetic memory elements, the NVRAM being bit-accessible. The hybrid non-volatile device further includes a non-volatile page-mode memory (PMM) made of resistive memory and organized into pages, the non-volatile PMM being page-accessible. Further included in the hybrid non-volatile memory device is a direct memory access (DMA) engine that is coupled to the NVRAM and the non-volatile PMM and transfers data between the NVRAM and the non-volatile PMM during a DMA operation.Type: GrantFiled: April 28, 2014Date of Patent: July 14, 2015Assignee: AVALANCHE TECHNOLOGY, INC.Inventors: Ravishankar Tadepalli, Rajiv Yadav Ranjan, Mehdi Asnaashari, Ngon Van Le, Parviz Keshtbod
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Publication number: 20150188036Abstract: A spin-transfer torque magnetic random access memory (STTMRAM) element includes a composite fixed layer formed on top of a substrate and a tunnel layer formed upon the fixed layer and a composite free layer formed upon the tunnel barrier layer. The magnetization direction of each of the composite free layer and fixed layer being substantially perpendicular to the plane of the substrate. The composite layers are made of multiple repeats of a bilayer unit which consists of a non-magnetic insulating layer and magnetic layer with thicknesses adjusted in a range that makes the magnetization having a preferred direction perpendicular to film plane.Type: ApplicationFiled: March 13, 2015Publication date: July 2, 2015Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
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Publication number: 20150188035Abstract: A spin-transfer torque magnetic random access memory (STTMRAM) element includes a composite fixed layer formed on top of a substrate and a tunnel layer formed upon the fixed layer and a composite free layer formed upon the tunnel barrier layer. The magnetization direction of each of the composite free layer and fixed layer being substantially perpendicular to the plane of the substrate. The composite layers are made of multiple repeats of a bilayer unit which consists of a non-magnetic insulating layer and magnetic layer with thicknesses adjusted in a range that makes the magnetization having a preferred direction perpendicular to film plane.Type: ApplicationFiled: March 13, 2015Publication date: July 2, 2015Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
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Patent number: 9070692Abstract: Chip packages are described with soft-magnetic shields that are included inside or attached externally to the package containing a MRAM chip. In one group of embodiments a single shield with vias for bonding wires is affixed to the surface of the MRAM chip having the contact pads. The limitation of shield to chip distance due to bonding wire is eliminated by VIA holes according to the invention which achieves minimal spacing between the shield and chip. A second shield without vias can be positioned on the opposite side of the chip from the first shield. In one group of embodiments a hardened ferro-fluid shield can be the only shield or the structure can include a shield with or without vias. One group of embodiments includes an external shield with vias for solder access to the package contact pads affixed to the outer surface of the package.Type: GrantFiled: January 12, 2013Date of Patent: June 30, 2015Assignee: Avalanche Technology, Inc.Inventors: Yuchen Zhou, Bernardo Sardinha, Rajiv Yadav Ranjan, Ebrahim Abedifard, Roger Klas Malmhall, Zihui Wang, Yiming Huai, Jing Zhang
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Spin-Transfer Torque Magnetic Random Access Memory (STTMRAM) with Perpendicular Laminated Free Layer
Publication number: 20150137293Abstract: A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element includes a fixed layer having a magnetization that is substantially fixed in one direction and a barrier layer formed on top of the fixed layer and a free layer. The free layer has a number of alternating laminates, each laminate being made of a magnetic layer and an insulating layer. The magnetic layer is switchable and formed on top of the barrier layer. The free layer is capable of switching its magnetization to a parallel or an anti-parallel state relative to the magnetization of the fixed layer during a write operation when bidirectional electric current is applied across the STTMRAM element. Magnetic layers of the laminates are ferromagnetically coupled to switch together as a single domain during the write operation and the magnetization of the fixed and free layers and the magnetic layers of the laminates have perpendicular anisotropy.Type: ApplicationFiled: January 30, 2015Publication date: May 21, 2015Inventors: Yiming Huai, Rajiv Yadav Ranjan, Roger K. Malmhall -
Spin-transfer torque magnetic random access memory (STTMRAM) with perpendicular laminated free layer
Patent number: 9025371Abstract: A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element includes a fixed layer having a magnetization that is substantially fixed in one direction and a barrier layer formed on top of the fixed layer and a free layer. The free layer has a number of alternating laminates, each laminate being made of a magnetic layer and an insulating layer. The magnetic layer is switchable and formed on top of the barrier layer. The free layer is capable of switching its magnetization to a parallel or an anti-parallel state relative to the magnetization of the fixed layer during a write operation when bidirectional electric current is applied across the STTMRAM element. Magnetic layers of the laminates are ferromagnetically coupled to switch together as a single domain during the write operation and the magnetization of the fixed and free layers and the magnetic layers of the laminates have perpendicular anisotropy.Type: GrantFiled: January 30, 2015Date of Patent: May 5, 2015Assignee: Avalanche Technology, Inc.Inventors: Yiming Huai, Rajiv Yadav Ranjan, Roger K. Malmhall -
Patent number: 9019758Abstract: A spin transfer torque magnetic random access memory (STTMRAM) element includes a composite fixed layer formed on top of a substrate and a tunnel layer formed upon the fixed layer and a composite free layer formed upon the tunnel barrier layer. The magnetization direction of each of the composite free layer and fixed layer being substantially perpendicular to the plane of the substrate. The composite layers are made of multiple repeats of a bi-layer unit which consists of a non-magnetic insulating layer and magnetic layer with thicknesses adjusted in a range that makes the magnetization having a preferred direction perpendicular to film plane.Type: GrantFiled: September 2, 2011Date of Patent: April 28, 2015Assignee: Avalanche Technology, Inc.Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall, Ioan Tudosa
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Patent number: 8981506Abstract: A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element is configured to store a state when electrical current is applied thereto. The perpendicular STTMRAM element includes a magnetization layer having a first free layer and a second free layer, separated by a non-magnetic separation layer (NMSL). The direction of magnetization of the first and second free layers each is in-plane prior to the application of electrical current and after the application of electrical current, the direction of magnetization of the second free layer becomes substantially titled out-of-plane and the direction of magnetization of the first free layer switches. Upon electrical current being discontinued, the direction of magnetization of the second free layer remains in a direction that is substantially opposite to that of the first free layer.Type: GrantFiled: June 19, 2013Date of Patent: March 17, 2015Assignee: Avalanche Technology, Inc.Inventors: Yuchen Zhou, Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Roger Klas Malmhall
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Spin-transfer torque magnetic random access memory (STTMRAM) with perpendicular laminated free layer
Patent number: 8982616Abstract: A perpendicular spin transfer torque magnetic random access memory (STTMRAM) element includes a fixed layer having a magnetization that is substantially fixed in one direction and a barrier layer formed on top of the fixed layer and a free layer. The free layer has a number of alternating laminates, each laminate being made of a magnetic layer and an insulating layer. The magnetic layer is switchable and formed on top of the barrier layer. The free layer is capable of switching its magnetization to a parallel or an anti-parallel state relative to the magnetization of the fixed layer during a write operation when bidirectional electric current is applied across the STTMRAM element. Magnetic layers of the laminates are ferromagnetically coupled to switch together as a single domain during the write operation and the magnetization of the fixed and free layers and the magnetic layers of the laminates have perpendicular anisotropy.Type: GrantFiled: November 26, 2012Date of Patent: March 17, 2015Assignee: Avalanche Technology, Inc.Inventors: Rajiv Yadav Ranjan, Roger Klas Malmhall, Yiming Huai -
Patent number: 8980649Abstract: In accordance with a method of the present invention, a method of manufacturing a magnetic random access memory (MRAM) cell and a corresponding structure thereof are disclosed to include a multi-stage manufacturing process. The multi-stage manufacturing process includes performing a front end on-line (FEOL) stage to manufacture logic and non-magnetic portions of the memory cell by forming an intermediate interlayer dielectric (ILD) layer, forming intermediate metal pillars embedded in the intermediate ILD layer, depositing a conductive metal cap on top of the intermediate ILD layer and the metal pillars, performing magnetic fabrication stage to make a magnetic material portion of the memory cell being manufactured, and performing back end on-line (BEOL) stage to make metal and contacts of the memory cell being manufactured.Type: GrantFiled: September 16, 2013Date of Patent: March 17, 2015Assignee: Avalanche Technology, Inc.Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
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Patent number: 8975088Abstract: Various embodiments of the invention relate to etching processes used in fabrication of MTJ cells in an MRAM device. The various embodiments can be used in combination with each other. The first embodiment adds a hard mask buffer layer between a hard mask and a top electrode. The second embodiment uses a multilayered etching hard mask. The third embodiment uses a multilayered top electrode structure including a first Cu layer under a second layer such as Ta. The fourth embodiment is a two-phase etching process used for the bottom electrode to remove re-deposited material while maintaining a more vertical sidewall etching profile. In the first phase the bottom electrode layer is removed using carbonaceous reactive ion etching until the endpoint. In the second phase an inert gas and/or oxygen plasma is used to remove the polymer that was deposited during the previous etching processes.Type: GrantFiled: July 30, 2013Date of Patent: March 10, 2015Assignee: Avalanche Technology, Inc.Inventors: Kimihiro Satoh, Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Parviz Keshtbod, Roger K. Malmhall
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Publication number: 20150061050Abstract: A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element is configured to store a state when electrical current is applied thereto. The perpendicular STTMRAM element includes a magnetization layer having a first free layer and a second free layer, separated by a non-magnetic separation layer (NMSL). The direction of magnetization of the first and second free layers each is in-plane prior to the application of electrical current and after the application of electrical current, the direction of magnetization of the second free layer becomes substantially titled out-of-plane and the direction of magnetization of the first free layer switches. Upon electrical current being discontinued, the direction of magnetization of the second free layer remains in a direction that is substantially opposite to that of the first free layer.Type: ApplicationFiled: June 19, 2013Publication date: March 5, 2015Inventors: Yuchen Zhou, Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Roger Klas Malmhall
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Patent number: 8947919Abstract: One embodiment of the present invention includes a diode-addressable current-induced magnetization switching (CIMS) memory element including a magnetic tunnel junction (MTJ) and a diode formed on top of the MTJ for addressing the MTJ.Type: GrantFiled: September 3, 2013Date of Patent: February 3, 2015Assignee: Avalanche Technology, Inc.Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod
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Patent number: 8917543Abstract: A multi-state spin-torque transfer magnetic random access memory (STTMRAM) is formed on a film and includes a first magnetic tunneling junctions (MTJ) having a first fixed layer, a first sub-magnetic tunnel junction (sub-MTJ) layer and a first free layer. The first fixed layer and first free layer each have a first magnetic anisotropy. The STTMRAM further includes a non-magnetic spacing layer formed on top of the first MTJ layer and a second MTJ formed on top of the non-magnetic spacing layer. The second MTJ has a second fixed layer, a second sub-MTJ layer and a second free layer. The second fixed and second free layers each have a second magnetic anisotropy, wherein at least one of the first or second magnetic anisotropy is perpendicular to the plane of the film.Type: GrantFiled: May 13, 2013Date of Patent: December 23, 2014Assignee: Avalanche Technology, Inc.Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod
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Patent number: 8885395Abstract: A magnetoresistive logic cell (MRLC) is described that includes two MTJs in series that share a common free layer (CFL). The relative magnetization orientations of the CFL and the switchable reference layer (SRL) in MTJ-1 dominate the overall resistance of the MRLC without regard to the fixed magnetization orientation of the nonswitchable reference layer in MTJ-2. The high resistance state of the MRLC occurs when the switchable reference and common free layers have opposite magnetization orientations. The low resistance state occurs when the orientations are the same. This behavior allows the MRLC to be used as a logical comparator. The CFL is switched by STT effect by application of selected relatively short voltage pulses that do not switch the SRL. The SRL is switched with reference to the CFL by a voltage effect generated by a selected longer voltage pulse that does not switch the CFL.Type: GrantFiled: February 22, 2012Date of Patent: November 11, 2014Assignee: Avalanche Technology, Inc.Inventors: Yuchen Zhou, Zihui Wang, Yiming Huai, Rajiv Yadav Ranjan, Roger K. Malmhall
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Patent number: 8860158Abstract: A STTMRAM element includes a magnetization layer made of a first free layer and a second free layer, separated by a non-magnetic separation layer (NMSL), with the first and second free layers each having in-plane magnetizations that act on each other through anti-parallel coupling. The direction of the magnetization of the first and second free layers each is in-plane prior to the application of electrical current to the STTMRAM element and thereafter, the direction of magnetization of the second free layer becomes substantially titled out-of-plane and the direction of magnetization of the first free layer switches. Upon electrical current being discontinued to the STTMRAM element, the direction of magnetization of the second free layer remains in a direction that is substantially opposite to that of the first free layer.Type: GrantFiled: June 19, 2013Date of Patent: October 14, 2014Assignee: Avalanche Technology, Inc.Inventors: Yuchen Zhou, Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Roger Klas Malmhall
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Publication number: 20140254245Abstract: A hybrid non-volatile memory device includes a non-volatile random access memory (NVRAM) having an array of magnetic memory elements, the NVRAM being bit-accessible. The hybrid non-volatile device further includes a non-volatile page-mode memory (PMM) made of resistive memory and organized into pages, the non-volatile PMM being page-accessible. Further included in the hybrid non-volatile memory device is a direct memory access (DMA) engine that is coupled to the NVRAM and the non-volatile PMM and transfers data between the NVRAM and the non-volatile PMM during a DMA operation.Type: ApplicationFiled: April 28, 2014Publication date: September 11, 2014Applicant: Avalanche Technology, Inc.Inventors: Ravishankar Tadepalli, Rajiv Yadav Ranjan, Mehdi Asnaashari, NGON VAN LE, Parviz Keshtbod
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Patent number: 8802451Abstract: Methods of fabricating MTJ arrays using two orthogonal line patterning steps are described. Embodiments are described that use a self-aligned double patterning method for one or both orthogonal line patterning steps to achieve dense arrays of MTJs with feature dimensions one half of the minimum photo lithography feature size (F). In one set of embodiments, the materials and thicknesses of the stack of layers that provide the masking function are selected so that after the initial set of mask pads have been patterned, a sequence of etching steps progressively transfers the mask pad shape through the multiple mask layer and down through all of the MTJ cell layers to the form the complete MTJ pillars. In another set of embodiments, the MTJ/BE stack is patterned into parallel lines before the top electrode layer is deposited.Type: GrantFiled: September 11, 2012Date of Patent: August 12, 2014Assignee: Avalanche Technology Inc.Inventors: Roger Klas Malmhall, Kimihiro Satoh, Jing Zhang, Parviz Keshtbod, Rajiv Yadav Ranjan
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Publication number: 20140197505Abstract: Chip packages are described with soft-magnetic shields that are included inside or attached externally to the package containing a MRAM chip. In one group of embodiments a single shield with vias for bonding wires is affixed to the surface of the MRAM chip having the contact pads. The limitation of shield to chip distance due to bonding wire is eliminated by VIA holes according to the invention which achieves minimal spacing between the shield and chip. A second shield without vias can be positioned on the opposite side of the chip from the first shield. In one group of embodiments a hardened ferro-fluid shield can be the only shield or the structure can include a shield with or without vias. One group of embodiments includes an external shield with vias for solder access to the package contact pads affixed to the outer surface of the package.Type: ApplicationFiled: January 12, 2013Publication date: July 17, 2014Applicant: AVALANCHE TECHNOLOGY INC.Inventors: Yuchen Zhou, Bernardo Sardinha, Rajiv Yadav Ranjan, Ebrahim Abedifard, Roger Klas Malmhall, Zihui Wang, Yiming Huai, Jing Zhang
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Patent number: 8779537Abstract: A spin transfer torque memory random access memory (STTMRAM) element is capable of switching states when electrical current is applied thereto for storing data and includes the following layers. An anti-ferromagnetic layer, a fixed layer formed on top of the anti-ferromagnetic layer, a barrier layer formed on top of the second magnetic layer of the fixed layer, and a free layer including a first magnetic layer formed on top of the barrier layer, a second magnetic layer formed on top of the first magnetic layer, a nonmagnetic insulating layer formed on top of the second magnetic layer and a third magnetic layer formed on top of the non-magnetic insulating layer. A capping layer is formed on top of the non-magnetic insulating layer.Type: GrantFiled: September 16, 2013Date of Patent: July 15, 2014Assignee: Avalanche Technology, Inc.Inventors: Yiming Huai, Rajiv Yadav Ranjan, Roger Klas Malmhall, Yuchen Zhou