Patents by Inventor Zihui Wang

Zihui Wang 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: 9831421
    Abstract: The present invention is directed to an MTJ memory element including a magnetic free layer structure which includes one or more magnetic free layers that have a same variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure comprising a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated therefrom by a perpendicular enhancement layer with the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer opposite the perpendicular enhancement layer; and a magnetic fixed layer comprising first and second magnetic fixed sublayers with the second magnetic fixed sublayer formed adjacent to the anti-ferromagnetic
    Type: Grant
    Filed: July 13, 2015
    Date of Patent: November 28, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Zihui Wang, Huadong Gan, Yiming Huai, Yuchen Zhou, Xiaobin Wang, Bing K. Yen, Xiaojie Hao
  • Publication number: 20170324027
    Abstract: The present invention is directed to a magnetic tunnel junction (MTJ) memory element including a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; a magnetic fixed layer exchange coupled to the magnetic reference layer structure through an anti-ferromagnetic coupling layer; a magnesium oxide layer formed adjacent to the magnetic fixed layer; and a metal layer comprising nickel and chromium formed adjacent to the magnesium oxide layer. The magnetic reference layer structure includes a first and a second magnetic reference layers with a first perpendicular enhancement layer (PEL) interposed therebetween. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof. The magnetic fixed layer has a second invariable magnetization direction opposite to the first invariable magnetization direction.
    Type: Application
    Filed: July 27, 2017
    Publication date: November 9, 2017
    Inventors: Yiming Huai, Huadong Gan, Zihui Wang
  • Publication number: 20170288137
    Abstract: The present invention is directed to an MTJ memory element including a magnetic free layer structure which includes one or more magnetic free layers that have a same variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure comprising a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated therefrom by a perpendicular enhancement layer with the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer opposite the perpendicular enhancement layer; and a magnetic fixed layer comprising first and second magnetic fixed sublayers with the second magnetic fixed sublayer formed adjacent to the anti-ferromagnetic
    Type: Application
    Filed: July 13, 2015
    Publication date: October 5, 2017
    Inventors: Zihui Wang, Huadong Gan, Yiming Huai, Yuchen Zhou, Xiaobin Wang, Bing K. Yen, Xiaojie Hao
  • Patent number: 9748471
    Abstract: The present invention is directed to an STT-MRAM device comprising a plurality of memory elements. Each of the memory elements includes an MTJ structure that comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; a first perpendicular enhancement layer (PEL) formed adjacent to the magnetic free layer structure; a magnetic dead layer formed adjacent to the first PEL; and a magnetic fixed layer exchange coupled to the magnetic reference layer structure through an anti-ferromagnetic coupling layer. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by a second PEL. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof.
    Type: Grant
    Filed: February 23, 2017
    Date of Patent: August 29, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Yuchen Zhou, Zihui Wang, Huadong Gan, Yiming Huai
  • Publication number: 20170236868
    Abstract: The present invention is directed to a spin-orbitronics device including an array of MTJs with each of the MTJs coupled to a respective one of a plurality of selection transistors; a plurality of transverse polarizing lines with each of the transverse polarizing lines coupled to a row of the MTJs along a first direction; a plurality of word lines with each of the word lines coupled to gates of a row of the selection transistors along a second direction; and a plurality of source lines with each of the source lines coupled to a row of the selection transistors along a direction substantially perpendicular to the second direction. Each MTJ includes a magnetic comparison layer structure having a pseudo-invariable magnetization direction, which is configured to switch between two stable states by passing a comparison current through one of the plurality of transverse polarizing lines formed adjacent to the magnetic comparison layer structure.
    Type: Application
    Filed: May 4, 2017
    Publication date: August 17, 2017
    Inventors: Parviz Keshtbod, Xiaobin Wang, Kimihiro Satoh, Zihui Wang, Huadong Gan
  • 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: 20170162781
    Abstract: The present invention is directed to an STT-MRAM device comprising a plurality of memory elements. Each of the memory elements includes an MTJ structure that comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; a first perpendicular enhancement layer (PEL) formed adjacent to the magnetic free layer structure; a magnetic dead layer formed adjacent to the first PEL; and a magnetic fixed layer exchange coupled to the magnetic reference layer structure through an anti-ferromagnetic coupling layer. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by a second PEL. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof.
    Type: Application
    Filed: February 23, 2017
    Publication date: June 8, 2017
    Inventors: Yuchen Zhou, Zihui Wang, Huadong Gan, Yiming Huai
  • Patent number: 9647202
    Abstract: The present invention is directed to an MRAM element comprising a plurality of magnetic tunnel junction (MTJ) memory elements. Each of the memory elements comprises a magnetic reference layer structure, which includes a first and a second magnetic reference layers with a tantalum perpendicular enhancement layer interposed therebetween, an insulating tunnel junction layer formed adjacent to the first magnetic reference layer opposite the tantalum perpendicular enhancement layer, and a magnetic free layer formed adjacent to the insulating tunnel junction layer. The first and second magnetic reference layers have a first fixed magnetization direction substantially perpendicular to the layer planes thereof.
    Type: Grant
    Filed: April 18, 2014
    Date of Patent: May 9, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Huadong Gan, Yuchen Zhou, Yiming Huai, Zihui Wang, Xiaobin Wang
  • Patent number: 9647032
    Abstract: The present invention is directed to a spin-orbitronics device including a magnetic comparison layer structure having a pseudo-invariable magnetization direction; a magnetic free layer structure whose variable magnetization direction can be switched by a switching current passing between the magnetic comparison layer structure and the magnetic free layer structure; an insulating tunnel junction layer interposed between the magnetic comparison layer structure and the magnetic free layer structure; and a non-magnetic transverse polarizing layer formed adjacent to the magnetic comparison layer structure. The pseudo-invariable magnetization direction of the magnetic comparison layer structure may be switched by passing a comparison current through the transverse polarizing layer along a direction that is substantially parallel to a layer plane of the transverse polarizing layer. The pseudo-invariable magnetization direction of the magnetic comparison layer structure is not switched by the switching current.
    Type: Grant
    Filed: August 20, 2015
    Date of Patent: May 9, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Xiaobin Wang, Parviz Keshtbod, Kimihiro Satoh, Zihui Wang, Huadong Gan
  • Patent number: 9634244
    Abstract: The present invention is directed to an MRAM element comprising a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween. The magnetic free layer structure has a variable magnetization direction substantially perpendicular to the layer plane thereof. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by a first non-magnetic perpendicular enhancement layer. The first and second magnetic reference layers have a first fixed magnetization direction substantially perpendicular to the layer plane thereof.
    Type: Grant
    Filed: March 24, 2016
    Date of Patent: April 25, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Huadong Gan, Yiming Huai, Zihui Wang, Yuchen Zhou
  • Patent number: 9608038
    Abstract: The present invention is directed to an STT-MRAM device comprising a plurality of memory elements. Each of the memory elements includes an MTJ structure in between a seed layer and a cap layer. The MTJ structure includes a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; and a magnetic fixed layer separated from the magnetic reference layer structure by an anti-ferromagnetic coupling layer. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by an intermediate magnetic reference layer. The first, second, and intermediate magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof.
    Type: Grant
    Filed: June 6, 2016
    Date of Patent: March 28, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Zihui Wang, Yuchen Zhou, Huadong Gan, Yiming Huai
  • Patent number: 9559144
    Abstract: The present invention is directed to a spin transfer torque (STT) MRAM device having a perpendicular magnetic tunnel junction (MTJ) memory element. The memory element includes a perpendicular MTJ structure in between a non-magnetic seed layer and a non-magnetic cap layer. The MTJ structure comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween, an anti-ferromagnetic coupling layer formed adjacent to the magnetic reference layer structure, and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. At least one of the magnetic free and reference layer structures includes a non-magnetic perpendicular enhancement layer, which improves the perpendicular anisotropy of magnetic layers adjacent thereto.
    Type: Grant
    Filed: June 3, 2015
    Date of Patent: January 31, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Huadong Gan, Yiming Huai, Yuchen Zhou, Zihui Wang, Xiaobin Wang, Bing K. Yen
  • Patent number: 9548334
    Abstract: The present invention is directed to a spin transfer torque (STT) MRAM device having a perpendicular magnetic tunnel junction (MTJ) memory element. The memory element includes a perpendicular MTJ structure in between a non-magnetic seed layer and a non-magnetic cap layer. The MTJ structure comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween, an anti-ferromagnetic coupling layer formed adjacent to the magnetic reference layer structure, and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. At least one of the magnetic free and reference layer structures includes a non-magnetic perpendicular enhancement layer, which improves the perpendicular anisotropy of magnetic layers adjacent thereto.
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: January 17, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Huadong Gan, Yuchen Zhou, Yiming Huai, Zihui Wang, Xiaobin Wang
  • Patent number: 9543506
    Abstract: The present invention is directed to an MTJ memory element including a magnetic free layer structure which comprises one or more magnetic free layers that have a same variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure comprising a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated therefrom by a perpendicular enhancement layer with the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer opposite the perpendicular enhancement layer; and a magnetic fixed layer comprising first and second magnetic fixed sublayers with the second magnetic fixed sublayer formed adjacent to the anti-ferromagnetic
    Type: Grant
    Filed: February 26, 2016
    Date of Patent: January 10, 2017
    Assignee: Avalanche Technology, Inc.
    Inventors: Huadong Gan, Yiming Huai, Yuchen Zhou, Zihui Wang, Xiaobin Wang, Bing K. Yen, Xiaojie Hao
  • Patent number: 9502092
    Abstract: MRAM devices that are switched by unipolar electron flow are described. Embodiments use arrays of cells that include a diode or transistor with a pMTJ. The switching between the high and low resistance states of the pMTJ is achieved by electron flow in the same direction, i.e. a unipolar flow. Embodiments of the invention include methods of operating unipolar MRAM devices that include a read step after a write step to verify the operation. Embodiments also include methods of operating unipolar MRAM devices that include an iterative stepped-voltage write process that includes a plurality of write-read steps that begin with a selected voltage for the write pulse for the first iteration and gradually increase the voltage for the write pulse for the next iteration until a successful read operation occurs.
    Type: Grant
    Filed: December 18, 2015
    Date of Patent: November 22, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Yuchen Zhou, Zihui Wang, Ebrahim Abedifard, Yiming Huai, Xiaojie Hao
  • Publication number: 20160284762
    Abstract: The present invention is directed to an STT-MRAM device comprising a plurality of memory elements. Each of the memory elements includes an MTJ structure in between a seed layer and a cap layer. The MTJ structure includes a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; and a magnetic fixed layer separated from the magnetic reference layer structure by an anti-ferromagnetic coupling layer. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by an intermediate magnetic reference layer. The first, second, and intermediate magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof.
    Type: Application
    Filed: June 6, 2016
    Publication date: September 29, 2016
    Inventors: Zihui Wang, Yuchen Zhou, Huadong Gan, Yiming Huai
  • Patent number: 9443577
    Abstract: The present invention is directed to a magnetic random access memory comprising a first magnetic tunnel junction (MTJ) including a first magnetic reference layer and a first magnetic free layer with a first insulating tunnel junction layer interposed therebetween; a second MTJ including a second magnetic reference layer and a second magnetic free layer with a second insulating tunnel junction layer interposed therebetween; and an anti-ferromagnetic coupling layer formed between the first and second variable magnetic free layers. The first and second magnetic free layers have a first and second magnetization directions, respectively, that are perpendicular to the layer planes thereof. The first magnetic reference layer has a first pseudo-fixed magnetization direction substantially perpendicular to the layer plane thereof.
    Type: Grant
    Filed: May 19, 2014
    Date of Patent: September 13, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Zihui Wang, Xiaobin Wang, Huadong Gan, Yuchen Zhou, Yiming Huai
  • Publication number: 20160211443
    Abstract: The present invention is directed to an MRAM element comprising a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween. The magnetic free layer structure has a variable magnetization direction substantially perpendicular to the layer plane thereof. The magnetic reference layer structure includes a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated from the first magnetic reference layer by a first non-magnetic perpendicular enhancement layer. The first and second magnetic reference layers have a first fixed magnetization direction substantially perpendicular to the layer plane thereof.
    Type: Application
    Filed: March 24, 2016
    Publication date: July 21, 2016
    Inventors: Huadong Gan, Yiming Huai, Zihui Wang, Yuchen Zhou
  • Patent number: 9396781
    Abstract: The present invention is directed to an STT-MRAM device including a plurality of magnetic tunnel junction (MTJ) memory elements. Each of the memory elements comprises a magnetic free layer structure and a magnetic reference layer structure with an insulating tunnel junction layer interposed therebetween; and a magnetic fixed layer separated from the magnetic reference layer structure by an anti-ferromagnetic coupling layer.
    Type: Grant
    Filed: February 5, 2014
    Date of Patent: July 19, 2016
    Assignee: Avalanche Technology, Inc.
    Inventors: Yuchen Zhou, Zihui Wang, Huadong Gan, Yiming Huai
  • Publication number: 20160204341
    Abstract: The present invention is directed to an MTJ memory element including a magnetic free layer structure which comprises one or more magnetic free layers that have a same variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure comprising a first magnetic reference layer formed adjacent to the insulating tunnel junction layer and a second magnetic reference layer separated therefrom by a perpendicular enhancement layer with the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer opposite the perpendicular enhancement layer; and a magnetic fixed layer comprising first and second magnetic fixed sublayers with the second magnetic fixed sublayer formed adjacent to the anti-ferromagnetic
    Type: Application
    Filed: February 26, 2016
    Publication date: July 14, 2016
    Inventors: Huadong Gan, Yiming Huai, Yuchen Zhou, Zihui Wang, Xiaobin Wang, Bing K. Yen, Xiaojie Hao