Patents by Inventor Kangho Lee

Kangho Lee 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: 9455014
    Abstract: Aspects for adjusting resistive memory write driver strength based on write error rate (WER) are disclosed. In one aspect, a write driver strength control circuit is provided to adjust a write current provided to a resistive memory based on a WER of the resistive memory. The write driver strength control circuit includes a tracking circuit configured to determine the WER of the resistive memory based on write operations performed on resistive memory elements. The write driver strength control circuit includes a write current calculator circuit configured to compare the WER to a target WER that represents the desired yield performance level of the resistive memory. A write current adjust circuit in the write driver strength control circuit is configured to adjust the write current based on this comparison. The write driver strength control circuit adjusts the write current to perform write operations while reducing write errors associated with breakdown voltage.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: September 27, 2016
    Assignee: QUALCOMM Incorporated
    Inventors: Kangho Lee, Taehyun Kim, Sungryul Kim, Seung Hyuk Kang, Jung Pill Kim
  • Publication number: 20160276009
    Abstract: Aspects for adjusting resistive memory write driver strength based on write error rate (WER) are disclosed. In one aspect, a write driver strength control circuit is provided to adjust a write current provided to a resistive memory based on a WER of the resistive memory. The write driver strength control circuit includes a tracking circuit configured to determine the WER of the resistive memory based on write operations performed on resistive memory elements. The write driver strength control circuit includes a write current calculator circuit configured to compare the WER to a target WER that represents the desired yield performance level of the resistive memory. A write current adjust circuit in the write driver strength control circuit is configured to adjust the write current based on this comparison. The write driver strength control circuit adjusts the write current to perform write operations while reducing write errors associated with breakdown voltage.
    Type: Application
    Filed: August 5, 2015
    Publication date: September 22, 2016
    Inventors: Kangho Lee, Taehyun Kim, Sungryul Kim, Seung Hyuk Kang, Jung Pill Kim
  • Publication number: 20160276407
    Abstract: Semiconductor devices and methods for forming a semiconductor device are disclosed. The method includes forming a storage unit of a magnetic memory cell. A bottom electrode and a fixed layer are formed. The fixed layer includes a composite spacer layer disposed on the bottom electrode. The composite spacer layer includes a base layer and an amorphous buffer layer disposed over the base layer. A reference layer is disposed on the composite spacer layer. The amorphous buffer layer serves as a template for the reference layer to have a desired crystalline structure in a desired orientation. At least one tunneling barrier layer is formed over the fixed layer. A storage layer is formed over the tunneling barrier layer and a top electrode is formed over the storage layer.
    Type: Application
    Filed: March 15, 2016
    Publication date: September 22, 2016
    Inventors: Vinayak Bharat NAIK, Kangho LEE, Taiebeh TAHMASEBI, Chenchen Jacob WANG
  • Publication number: 20160276581
    Abstract: A magnetic tunnel junction (MTJ) device includes a free layer. The MTJ also includes a barrier layer coupled to the free layer. The MTJ also has a fixed layer, coupled to the barrier layer. The fixed layer includes a first synthetic antiferromagnetic (SAF) multilayer having a first perpendicular magnetic anisotropy (PMA) and a first damping constant. The fixed layer also includes a second SAF multilayer having a second perpendicular magnetic anisotropy (PMA) and a second damping constant lower than the first damping constant. The first SAF multilayer is closer to the barrier layer than the second SAF multilayer. The fixed layer also includes a SAF coupling layer between the first and the second SAF multilayers.
    Type: Application
    Filed: May 31, 2016
    Publication date: September 22, 2016
    Inventors: Chando PARK, Kangho LEE, Seung Hyuk KANG
  • Publication number: 20160267961
    Abstract: Methods and apparatus relating to spin-orbit-torque magnetoresistive random access memory with voltage-controlled anisotropy are disclosed. In an example, disclosed is a three-terminal magnetic tunnel junction (MTJ) storage element that is programmed via a combination of voltage-controlled magnetic anisotropy (VCMA) and spin-orbit torque (SOT) techniques. Also disclosed is a memory controller configured to program the three-terminal MTJ storage element via VCMA and SOT techniques. The disclosed devices improve efficiency over conventional devices by using less write energy, while having a design that is simpler and more scalable than conventional devices.
    Type: Application
    Filed: May 19, 2016
    Publication date: September 15, 2016
    Inventors: Kangho LEE, Jimmy KAN, Seung Hyuk KANG
  • Patent number: 9444035
    Abstract: A magnetic tunnel junction (MTJ) device includes a pinned layer, a tunnel barrier layer on the pinned layer, and a free layer on the tunnel barrier layer. The MTJ device also includes a perpendicular magnetic anisotropic (PMA) enhancement layer on the free layer, a capping layer on the PMA enhancement layer, and a conductive path electrically shorting the capping layer, the PMA enhancement layer and the free layer. A method of fabricating a perpendicular magnetic tunnel junction (pMTJ) device includes forming a capping layer, a perpendicular magnetic anisotropic (PMA) enhancement layer and a free layer. The method also includes forming a conductive layer to short the capping layer, the PMA enhancement layer and the free layer.
    Type: Grant
    Filed: September 10, 2014
    Date of Patent: September 13, 2016
    Assignee: QUALCOMM INCORPORATED
    Inventors: Chando Park, Kangho Lee, Jimmy Kan, Matthias Georg Gottwald, Xiaochun Zhu, Seung Hyuk Kang
  • Publication number: 20160260891
    Abstract: A device and a method of forming a device are presented. A substrate is provided. The substrate includes circuit component formed on a substrate surface. Back end of line processing is performed to form an upper inter level dielectric (ILD) layer over the substrate. The upper ILD layer includes a plurality of ILD levels. A magnetic tunneling junction (MTJ) stack is formed in between adjacent ILD levels of the upper ILD layer. The MTJ stack comprises a free layer, a tunneling barrier layer and a fixed layer. The fixed layer includes a polarizer layer, a composite texture breaking layer which includes a ruthenium layer and a synthetic antiferromagnetic (SAF) layer.
    Type: Application
    Filed: March 4, 2016
    Publication date: September 8, 2016
    Inventors: Taiebeh TAHMASEBI, Kangho LEE, Vinayak Bharat NAIK
  • Publication number: 20160260892
    Abstract: A device and a method of forming a device are presented. A substrate is provided. The substrate includes circuit component formed on a substrate surface. Back end of line processing is performed to form an upper inter level dielectric (ILD) layer over the substrate. The upper ILD layer includes a plurality of ILD levels. A magnetic tunneling junction (MTJ) stack is formed in between adjacent ILD levels of the upper ILD layer. The MTJ stack includes a free layer, a tunneling barrier layer and a fixed layer. The fixed layer includes a polarizer layer, a composite texture breaking layer which includes a first magnesium layer and a synthetic antiferromagnetic (SAF) layer.
    Type: Application
    Filed: March 4, 2016
    Publication date: September 8, 2016
    Inventors: Taiebeh TAHMASEBI, Kangho LEE, Vinayak Bharat NAIK
  • Publication number: 20160233418
    Abstract: A magnetic tunnel junction (MTJ) device in a magnetoresistive random access memory (MRAM) and method of making the same are provided to achieve a high tunneling magnetoresistance (TMR), a high perpendicular magnetic anisotropy (PMA), good data retention, and a high level of thermal stability. The MTJ device includes a first free ferromagnetic layer, a synthetic antiferromagnetic (SAF) coupling layer, and a second free ferromagnetic layer, where the first and second free ferromagnetic layers have opposite magnetic moments.
    Type: Application
    Filed: April 19, 2016
    Publication date: August 11, 2016
    Inventors: Chando PARK, Matthias Georg GOTTWALD, Kangho LEE, Seung Hyuk KANG
  • Publication number: 20160232959
    Abstract: Methods and apparatus relating to spin-orbit-torque magnetoresistive random access memory with voltage-controlled anisotropy are disclosed. In an example, disclosed is a three-terminal magnetic tunnel junction (MTJ) storage element that is programmed via a combination of voltage-controlled magnetic anisotropy (VCMA) and spin-orbit torque (SOT) techniques. Also disclosed is a memory controller configured to program the three-terminal MTJ storage element via VCMA and SOT techniques. The disclosed devices improve efficiency over conventional devices by using less write energy, while having a design that is simpler and more scalable than conventional devices. The disclosed devices also have increased thermal stability without increasing required switching current, as critical switching current between states is essentially the same.
    Type: Application
    Filed: February 9, 2015
    Publication date: August 11, 2016
    Inventors: Kangho LEE, Jimmy KAN, Seung Hyuk KANG
  • Publication number: 20160225817
    Abstract: A semiconductor device includes a first magnetic tunnel junction (MTJ) device, a second MTJ device, and a top electrode. The first MTJ device includes a barrier layer. The second MTJ device includes the barrier layer. The top electrode is coupled to the first MTJ device and the second MTJ device.
    Type: Application
    Filed: January 29, 2015
    Publication date: August 4, 2016
    Inventors: Vladimir Machkaoutsan, Matthias Georg Gottwald, Mustafa Badaroglu, Jimmy Kan, Kangho Lee, Yu Lu, Chando Park
  • Patent number: 9385309
    Abstract: A method for fabricating a perpendicular magnetic tunnel junction (pMTJ) device includes growing a seed layer on a first electrode of the pMTJ device. The seed layer has a uniform predetermined crystal orientation along a growth axis. The method also includes planarizing the seed layer while maintaining the uniform predetermined crystal orientation of the seed layer.
    Type: Grant
    Filed: July 17, 2014
    Date of Patent: July 5, 2016
    Assignee: QUALCOMM INCORPORATED
    Inventors: Matthias Georg Gottwald, Jimmy Kan, Kangho Lee, Chando Park, Seung Hyuk Kang
  • Patent number: 9379314
    Abstract: A magnetic tunnel junction (MTJ) device includes a free layer. The MTJ also includes a barrier layer coupled to the free layer. The MTJ also has a fixed layer, coupled to the barrier layer. The fixed layer includes a first synthetic antiferromagnetic (SAF) multilayer having a first perpendicular magnetic anisotropy (PMA) and a first damping constant. The fixed layer also includes a second SAF multilayer having a second perpendicular magnetic anisotropy (PMA) and a second damping constant lower than the first damping constant. The first SAF multilayer is closer to the barrier layer than the second SAF multilayer. The fixed layer also includes a SAF coupling layer between the first and the second SAF multilayers.
    Type: Grant
    Filed: December 17, 2013
    Date of Patent: June 28, 2016
    Assignee: QUALCOMM INCORPORATED
    Inventors: Chando Park, Kangho Lee, Seung Hyuk Kang
  • Publication number: 20160181508
    Abstract: A material stack of a synthetic anti-ferromagnetic (SAF) reference layer of a perpendicular magnetic tunnel junction (MTJ) may include an SAF coupling layer. The material stack may also include and an amorphous spacer layer on the SAF coupling layer. The amorphous spacer layer may include an alloy or multilayer of tantalum and cobalt or tantalum and iron or cobalt and iron and tantalum. The amorphous spacer layer may also include a treated surface of the SAF coupling layer.
    Type: Application
    Filed: December 23, 2014
    Publication date: June 23, 2016
    Inventors: Kangho LEE, Jimmy KAN, Xiaochun ZHU, Matthias Georg GOTTWALD, Chando PARK, Seung Hyuk KANG
  • Patent number: 9368715
    Abstract: A memory cell includes a magnetic tunnel junction (MTJ) structure that includes a free layer coupled to a bit line and a pinned layer. A magnetic moment of the free layer is substantially parallel to a magnetic moment of the pinned layer in a first state and substantially antiparallel to the magnetic moment of the pinned layer in a second state. The pinned layer has a physical dimension to produce an offset magnetic field corresponding to a first switching current of the MTJ structure to enable switching between the first state and the second state when a first voltage is applied from the bit line to a source line coupled to an access transistor and a second switching current to enable switching between the second state and the first state when the first voltage is applied from the source line to the bit line.
    Type: Grant
    Filed: August 10, 2015
    Date of Patent: June 14, 2016
    Assignee: QUALCOMM Incorporated
    Inventors: Kangho Lee, Seung Kang, Xiaochun Zhu
  • Patent number: 9368232
    Abstract: In a particular embodiment, a method includes controlling a temperature within a chamber while applying a magnetic field. A device including a memory array is located in the chamber. The method includes applying a magnetic field to the memory array and testing the memory array during application of the magnetic field to the memory array at a target temperature.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: June 14, 2016
    Assignee: Qualcomm Incorporated
    Inventors: Kangho Lee, Wah Nam Hsu, Xiao Lu, Seung H. Kang
  • Publication number: 20160155931
    Abstract: An apparatus includes a capping layer disposed on top of a free layer. The apparatus also includes a magnetic etch stop layer disposed on top of the capping layer. The capping layer and the magnetic etch stop layer are included in a spin-transfer torque magnetoresistive random access memory (STT-MRAM) magnetic tunnel junction (MTJ) device.
    Type: Application
    Filed: December 2, 2014
    Publication date: June 2, 2016
    Inventors: Kangho Lee, Chando Park, Jimmy Kan, Matthias Georg Gottwald, Xiaochun Zhu, Seung Hyuk Kang
  • Publication number: 20160149388
    Abstract: A busbar kit is provided. The busbar kit electrically connects a circuit breaker and a main busbar, and comprises an insulating case having an inner space, a branch busbar disposed in the insulating case such that the branch busbar is spaced apart from the main busbar and crosses over the main busbar, and a busbar connector for electrically connecting the main busbar and the branch busbar.
    Type: Application
    Filed: June 12, 2014
    Publication date: May 26, 2016
    Inventor: Kangho LEE
  • Patent number: 9343135
    Abstract: One feature pertains to a method of implementing a physically unclonable function. The method includes initializing an array of magnetoresistive random-access memory (MRAM) cells to a first logical state, where each of the MRAM cells have a random transition voltage that is greater than a first voltage and less than a second voltage. The transition voltage represents a voltage level that causes the MRAM cells to transition from the first logical state to a second logical state. The method further includes applying a programming signal voltage to each of the MRAM cells of the array to cause at least a portion of the MRAM cells of the array to randomly change state from the first logical state to the second logical state, where the programming signal voltage is greater than the first voltage and less than the second voltage.
    Type: Grant
    Filed: November 5, 2013
    Date of Patent: May 17, 2016
    Assignee: QUALCOMM Incorporated
    Inventors: Xiaochun Zhu, Steven M. Millendorf, Xu Guo, David M. Jacobson, Kangho Lee, Seung H. Kang, Matthew Michael Nowak
  • Publication number: 20160125953
    Abstract: A one time programming (OTP) apparatus unit cell includes magnetic tunnel junctions (MTJs) with reversed connections for placing the MTJ in an anti-parallel resistance state during programming. Increased MTJ resistance in its anti-parallel resistance state causes a higher programming voltage which reduces programming time and programming current.
    Type: Application
    Filed: January 13, 2016
    Publication date: May 5, 2016
    Inventors: Jung Pill Kim, Taehyun Kim, Kangho Lee, Seung H. Kang, Xia Li, Wah Nam Hsu