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).

  • Patent number: 11678586
    Abstract: A spin-transfer torque magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL. The second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.
    Type: Grant
    Filed: January 9, 2013
    Date of Patent: June 13, 2023
    Assignee: Avalanche Technology, Inc.
    Inventors: Yiming Huai, Yuchen Zhou, Jing Zhang, Roger Klas Malmhall, Ioan Tudosa, Rajiv Yadav Ranjan
  • Publication number: 20190148622
    Abstract: A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.
    Type: Application
    Filed: January 9, 2013
    Publication date: May 16, 2019
    Applicant: Avalanche Technology, Inc.
    Inventors: Yiming Huai, Yuchen Zhou, Jing Zhang, Roger Klas Malmhall, Ioan Tudosa, Rajiv Yadav Ranjan
  • Patent number: 9793003
    Abstract: A memory device having features of the present invention comprises a reprogrammable memory portion including therein a first plurality of magnetic tunnel junctions (MTJs) whose resistance is switchable; and a one-time-programmable (OTP) memory portion including therein a second plurality of MTJs whose resistance is switchable and a third plurality of MTJs whose resistance is fixed. Each MTJ of the first, second, and third plurality of MTJs includes a magnetic free layer having a magnetization direction substantially perpendicular to a layer plane thereof and a magnetic reference layer having a fixed magnetization direction substantially perpendicular to a layer plane thereof. The second plurality of MTJs represents one of two logical states and the third plurality of MTJs represents the other one of the two logical states.
    Type: Grant
    Filed: September 14, 2016
    Date of Patent: October 17, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Ebrahim Abedifard, Uday Chandrasekhar, Rajiv Yadav Ranjan, Yiming Huai
  • Patent number: 9679625
    Abstract: An STTMRAM element includes a magnetic tunnel junction (MTJ) having a perpendicular magnetic orientation. The MTJ includes a barrier layer, a free layer formed on top of the barrier layer and having a magnetic orientation that is perpendicular and switchable relative to the magnetic orientation of the fixed layer. The magnetic orientation of the free layer switches when electrical current flows through the STTMRAM element. A switching-enhancing layer (SEL), separated from the free layer by a spacer layer, is formed on top of the free layer and has an in-plane magnetic orientation and generates magneto-static fields onto the free layer, causing the magnetic moments of the outer edges of the free layer to tilt with an in-plane component while minimally disturbing the magnetic moment at the center of the free layer to ease the switching of the free layer and to reduce the threshold voltage/current.
    Type: Grant
    Filed: November 2, 2015
    Date of Patent: June 13, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Jing Zhang, Yiming Huai, Rajiv Yadav Ranjan, Yuchen Zhou, Zihui Wang, Xiaojie Hao
  • Publication number: 20170076818
    Abstract: A memory device having features of the present invention comprises a reprogrammable memory portion including therein a first plurality of magnetic tunnel junctions (MTJs) whose resistance is switchable; and a one-time-programmable (OTP) memory portion including therein a second plurality of MTJs whose resistance is switchable and a third plurality of MTJs whose resistance is fixed. Each MTJ of the first, second, and third plurality of MTJs includes a magnetic free layer having a magnetization direction substantially perpendicular to a layer plane thereof and a magnetic reference layer having a fixed magnetization direction substantially perpendicular to a layer plane thereof. The second plurality of MTJs represents one of two logical states and the third plurality of MTJs represents the other one of the two logical states.
    Type: Application
    Filed: September 14, 2016
    Publication date: March 16, 2017
    Inventors: Ebrahim Abedifard, Uday Chandrasekhar, Rajiv Yadav Ranjan, Yiming Huai
  • Patent number: 9478279
    Abstract: The present invention is directed to a multi-state current-switching magnetic memory element configured to store a state by current flowing therethrough to switch the state including two or more magnetic tunneling junctions (MTJs) coupled in parallel between a top electrode and a bottom electrode. Each MTJ includes a free layer with a switchable magnetic orientation perpendicular to a layer plane thereof, a fixed layer with a fixed magnetic orientation perpendicular to a layer plane thereof, and a barrier layer interposed between the free layer and the fixed layer. The magnetic memory element is operable to store more than one bit of information.
    Type: Grant
    Filed: May 6, 2016
    Date of Patent: October 25, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9444039
    Abstract: 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: Grant
    Filed: March 13, 2015
    Date of Patent: September 13, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
  • Publication number: 20160254046
    Abstract: The present invention is directed to a multi-state current-switching magnetic memory element configured to store a state by current flowing therethrough to switch the state including two or more magnetic tunneling junctions (MTJs) coupled in parallel between a top electrode and a bottom electrode. Each MTJ includes a free layer with a switchable magnetic orientation perpendicular to a layer plane thereof, a fixed layer with a fixed magnetic orientation perpendicular to a layer plane thereof, and a barrier layer interposed between the free layer and the fixed layer. The magnetic memory element is operable to store more than one bit of information.
    Type: Application
    Filed: May 6, 2016
    Publication date: September 1, 2016
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9419210
    Abstract: The present invention is directed to a spin transfer torque magnetic random access memory (STTMRAM) element comprising a composite free layer including one or more stacks of a bilayer unit that comprises an insulator layer and a magnetic layer with the magnetic layer having a variable magnetization direction substantially perpendicular to a layer plane thereof; a magnetic pinned layer having a first fixed magnetization direction substantially perpendicular to a layer plane thereof; a tunnel barrier layer formed between the composite free layer and the magnetic pinned layer; and a magnetic fixed layer coupled to the magnetic pinned layer through an anti-ferromagnetic coupling layer. The magnetic fixed layer has a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to the first fixed magnetization direction.
    Type: Grant
    Filed: March 16, 2016
    Date of Patent: August 16, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
  • Publication number: 20160197269
    Abstract: The present invention is directed to a spin transfer torque magnetic random access memory (STTMRAM) element comprising a composite free layer including one or more stacks of a bilayer unit that comprises an insulator layer and a magnetic layer with the magnetic layer having a variable magnetization direction substantially perpendicular to a layer plane thereof; a magnetic pinned layer having a first fixed magnetization direction substantially perpendicular to a layer plane thereof; a tunnel barrier layer formed between the composite free layer and the magnetic pinned layer; and a magnetic fixed layer coupled to the magnetic pinned layer through an anti-ferromagnetic coupling layer. The magnetic fixed layer has a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to the first fixed magnetization direction.
    Type: Application
    Filed: March 16, 2016
    Publication date: July 7, 2016
    Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
  • Patent number: 9349941
    Abstract: The present invention is directed to a multi-state current-switching magnetic memory element configured to store a state by current flowing therethrough to switch the state. The magnetic memory element includes a stack of two or more magnetic tunneling junctions (MTJs) with each MTJ including a free layer with a switchable magnetic orientation perpendicular to a layer plane thereof, a barrier layer, and a fixed layer with a fixed magnetic orientation perpendicular to a layer plane thereof. Each MTJ is separated from other MTJs in the stack by at least an isolation layer. The stack of MTJs may store more than one bit of information. The free layer of each MTJ has a switching current threshold different from free layers of other MTJs in the stack.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: May 24, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9337413
    Abstract: One embodiment of the present invention includes a multi-state current-switching magnetic memory element that includes a stack of two or more magnetic tunneling junctions (MTJs), each MTJ having a free layer and being separated from other MTJs in the stack by a seeding layer formed upon an isolation layer. The stack is for storing more than one bit of information, wherein different levels of current applied to the memory element cause switching to different states.
    Type: Grant
    Filed: October 29, 2015
    Date of Patent: May 10, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9318179
    Abstract: 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: Grant
    Filed: March 13, 2015
    Date of Patent: April 19, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Yiming Huai, Jing Zhang, Rajiv Yadav Ranjan, Yuchen Zhou, Roger Klas Malmhall
  • Publication number: 20160079517
    Abstract: The present invention is directed to a multi-state current-switching magnetic memory element configured to store a state by current flowing therethrough to switch the state. The magnetic memory element includes a stack of two or more magnetic tunneling junctions (MTJs) with each MTJ including a free layer with a switchable magnetic orientation perpendicular to a layer plane thereof, a barrier layer, and a fixed layer with a fixed magnetic orientation perpendicular to a layer plane thereof. Each MTJ is separated from other MTJs in the stack by at least an isolation layer. The stack of MTJs may store more than one bit of information. The free layer of each MTJ has a switching current threshold different from free layers of other MTJs in the stack.
    Type: Application
    Filed: November 17, 2015
    Publication date: March 17, 2016
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Publication number: 20160055893
    Abstract: An STTMRAM element includes a magnetic tunnel junction (MTJ) having a perpendicular magnetic orientation. The MTJ includes a barrier layer, a free layer formed on top of the barrier layer and having a magnetic orientation that is perpendicular and switchable relative to the magnetic orientation of the fixed layer. The magnetic orientation of the free layer switches when electrical current flows through the STTMRAM element. A switching-enhancing layer (SEL), separated from the free layer by a spacer layer, is formed on top of the free layer and has an in-plane magnetic orientation and generates magneto-static fields onto the free layer, causing the magnetic moments of the outer edges of the free layer to tilt with an in-plane component while minimally disturbing the magnetic moment at the center of the free layer to ease the switching of the free layer and to reduce the threshold voltage/current.
    Type: Application
    Filed: November 2, 2015
    Publication date: February 25, 2016
    Inventors: Jing Zhang, Yiming Huai, Rajiv Yadav Ranjan, Yuchen Zhou, Zihui Wang, Xiaojie Hao
  • Publication number: 20160049184
    Abstract: One embodiment of the present invention includes a multi-state current-switching magnetic memory element includes a stack of two or more magnetic tunneling junctions (MTJs), each MTJ having a free layer and being separated from other MTJs in the stack by a seeding layer formed upon an isolation layer, the stack for storing more than one bit of information, wherein different levels of current applied to the memory element causes switching to different states.
    Type: Application
    Filed: October 29, 2015
    Publication date: February 18, 2016
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9218866
    Abstract: One embodiment of the present invention includes a multi-state current-switching magnetic memory element includes a stack of two or more magnetic tunneling junctions (MTJs), each MTJ having a free layer and being separated from other MTJs in the stack by a seeding layer formed upon an isolation layer, the stack for storing more than one bit of information, wherein different levels of current applied to the memory element causes switching to different states.
    Type: Grant
    Filed: May 13, 2013
    Date of Patent: December 22, 2015
    Assignee: AVALANCHE TECHNOLOGY, INC.
    Inventors: Rajiv Yadav Ranjan, Parviz Keshtbod, Roger Klas Malmhall
  • Patent number: 9196332
    Abstract: An STTMRAM element includes a magnetic tunnel junction (MTJ) having a perpendicular magnetic orientation. The MTJ includes a barrier layer, a free layer formed on top of the barrier layer and having a magnetic orientation that is perpendicular and switchable relative to the magnetic orientation of the fixed layer. The magnetic orientation of the free layer switches when electrical current flows through the STTMRAM element. A switching-enhancing layer (SEL), separated from the free layer by a spacer layer, is formed on top of the free layer and has an in-plane magnetic orientation and generates magneto-static fields onto the free layer, causing the magnetic moments of the outer edges of the free layer to tilt with an in-plane component while minimally disturbing the magnetic moment at the center of the free layer to ease the switching of the free layer and to reduce the threshold voltage/current.
    Type: Grant
    Filed: June 15, 2011
    Date of Patent: November 24, 2015
    Assignee: Avalanche Technology, Inc.
    Inventors: Jing Zhang, Yuchen Zhou, Rajiv Yadav Ranjan, Yiming Huai
  • Patent number: 9166154
    Abstract: Fabrication methods using Ion Beam Etching (IBE) for MRAM cell memory elements are described. In embodiments of the invention the top electrode and MTJ main body are etched with one mask using reactive etching such as RIE or magnetized inductively coupled plasma (MICP) for improved selectivity, then the bottom electrode is etched using IBE as specified in various alternative embodiments which include selection of incident angles, wafer rotational rate profiles and optional passivation layer deposited prior to the IBE. The IBE according to the invention etches the bottom electrode without the need for an additional mask by using the layer stack created by the first etching phase as the mask. This makes the bottom electrode self-aligned to MTJ. The IBE also achieves MTJ sidewall cleaning without the need for an additional step.
    Type: Grant
    Filed: December 4, 2013
    Date of Patent: October 20, 2015
    Assignee: Avalance Technology, Inc.
    Inventors: Kimihiro Satoh, Dong Ha Jung, Jing Zhang, Benjamin Chen, Yiming Huai, Rajiv Yadav Ranjan, Yuchen Zhou
  • Patent number: RE47975
    Abstract: An STTMRAM element includes a magnetic tunnel junction (MTJ) having a perpendicular magnetic orientation. The MTJ includes a barrier layer, a free layer formed on top of the barrier layer and having a magnetic orientation that is perpendicular and switchable relative to the magnetic orientation of the fixed layer. The magnetic orientation of the free layer switches when electrical current flows through the STTMRAM element. A switching-enhancing layer (SEL), separated from the free layer by a spacer layer, is formed on top of the free layer and has an in-plane magnetic orientation and generates magneto-static fields onto the free layer, causing the magnetic moments of the outer edges of the free layer to tilt with an in-plane component while minimally disturbing the magnetic moment at the center of the free layer to ease the switching of the free layer and to reduce the threshold voltage/current.
    Type: Grant
    Filed: August 10, 2018
    Date of Patent: May 5, 2020
    Assignee: Avalanche Technology, Inc.
    Inventors: Jing Zhang, Yiming Huai, Rajiv Yadav Ranjan, Yuchen Zhou, Zihui Wang, Xiaojie Hao