Patents by Inventor Yingda Dong

Yingda Dong 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).

  • Publication number: 20200006375
    Abstract: A three-dimensional memory device includes alternating stacks of insulating strips and electrically conductive strips located over a substrate and laterally spaced apart among one another by line trenches. The line trenches laterally extend along a first horizontal direction and are spaced apart along a second horizontal direction. Each line trench fill structure includes a laterally undulating dielectric rail having a laterally undulating width along the second horizontal direction and extending along the first horizontal direction and a row of memory stack structures located at neck regions of the laterally undulating dielectric rail.
    Type: Application
    Filed: June 27, 2018
    Publication date: January 2, 2020
    Inventors: Fei Zhou, Yingda Dong, Raghuveer S. Makala
  • Patent number: 10522232
    Abstract: Apparatuses and techniques are described for reducing an injection type of program disturb in a memory device. A voltage on a selected word line is increased in a first step from an initial level such as 0 V to an intermediate, pass level such as Vpass, and in a second step from Vpass to a peak program level of Vpgm. A voltage on an adjacent unselected word line can be increased from the initial level to Vpass and then temporarily increased to an elevated level of Vpass_el during the second step increase on the selected word line. This helps reduce the magnitude of a channel gradient between the selected word line and the adjacent word line. The increase to Vpass_el may be implemented for program loops in the later part of a program operation, when Vpgm and the risk of program disturb is relatively high.
    Type: Grant
    Filed: May 18, 2018
    Date of Patent: December 31, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Hong-Yan Chen, Yingda Dong
  • Publication number: 20190371402
    Abstract: Methods and systems for improving the reliability of stored data in the presence of cross-temperature variation are described. To reduce the number of data errors caused by cross-temperature variation, two or more sensing passes may be performed corresponding with two or more different sensing times. The amount of shifting in the memory cell threshold voltages may be determined on a per-bit basis or on a cell-by-cell basis based on the sensing operations performed during the two or more sensing passes. The stored data states may be assigned based on the amount of shifting in the memory cell threshold voltages during the two or more sensing passes and the type of cross-temperature variation present (e.g., whether the memory cells were programmed at a temperature above 65 degrees Celsius and read back at a temperature below 25 degrees Celsius).
    Type: Application
    Filed: September 24, 2018
    Publication date: December 5, 2019
    Applicant: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Lei Lin, Wei Zhao, Henry Chin, Yingda Dong
  • Patent number: 10497711
    Abstract: A three-dimensional non-volatile memory is provided with reduced programming variation across word lines. The gate lengths of word lines decrease from the top to the bottom of the memory hole. Increased programming speeds due to a narrow memory hole are offset by a smaller gate length at corresponding positions. A blocking dielectric thickness may also be varied, independently or in combination with a variable word line thickness. The blocking dielectric is formed with a horizontal thickness that is larger at regions adjacent to the lower word line layers and smaller at regions adjacent to the upper word line layers. The larger thickness at the lower word line layers reduces the programming speed in the memory hole for the lower word lines relative to the upper word lines. A variance in programming speed resulting from differences in memory hole diameter may be offset by a corresponding variance in blocking dielectric thickness.
    Type: Grant
    Filed: December 19, 2017
    Date of Patent: December 3, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Ashish Baraskar, Liang Pang, Yanli Zhang, Raghuveer Makala, Yingda Dong
  • Publication number: 20190355429
    Abstract: Apparatuses and techniques are described for reducing an injection type of program disturb in a memory device. A voltage on a selected word line is increased in a first step from an initial level such as 0 V to an intermediate, pass level such as Vpass, and in a second step from Vpass to a peak program level of Vpgm. A voltage on an adjacent unselected word line can be increased from the initial level to Vpass and then temporarily increased to an elevated level of Vpass_el during the second step increase on the selected word line. This helps reduce the magnitude of a channel gradient between the selected word line and the adjacent word line. The increase to Vpass_el may be implemented for program loops in the later part of a program operation, when Vpgm and the risk of program disturb is relatively high.
    Type: Application
    Filed: May 18, 2018
    Publication date: November 21, 2019
    Applicant: SanDisk Technologies LLC
    Inventors: Hong-Yan Chen, Yingda Dong
  • Patent number: 10461095
    Abstract: A non-volatile storage element is provided that includes a control gate, a blocking layer including a ferroelectric material, a charge storage region, and a tunneling layer. The blocking layer is disposed between the control gate and the charge storage region, and the charge storage region is disposed between the tunneling layer and the blocking layer.
    Type: Grant
    Filed: March 28, 2018
    Date of Patent: October 29, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Patent number: 10453861
    Abstract: A non-volatile storage element including a control gate, a tunneling layer, a charge storage region, and a blocking layer including a ferroelectric material. The tunneling layer is disposed between the control gate and the charge storage region, and the charge storage region is disposed between the tunneling layer and the blocking layer.
    Type: Grant
    Filed: March 28, 2018
    Date of Patent: October 22, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Patent number: 10453862
    Abstract: A memory cell is provided that includes a control gate, a tunneling layer, a charge storage region, a blocking layer including a ferroelectric material, a semiconductor channel, and a source region and a drain region each disposed adjacent the semiconductor channel. The tunneling layer is disposed between the control gate and the charge storage region, the charge storage region is disposed between the tunneling layer and the blocking layer, and the blocking layer is disposed above the semiconductor channel.
    Type: Grant
    Filed: March 28, 2018
    Date of Patent: October 22, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Patent number: 10446244
    Abstract: Apparatuses and techniques are described for programming memory cells with a narrow threshold voltage (Vth) distribution in a memory device. In one approach, the final pass of a multi-pass program operation on a word line WLn includes applying a variable voltage to WLn+1 during verify tests on WLn. The variable voltage (Vread) can be an increasing function of the verify voltage on WLn, and thus a function of the data state for which the verify test is performed. In one approach, Vread on WLn+1 is stepped up with each increase in the verify voltage on WLn. The step size in Vread can be the same as, or different than, the step size in the verify voltage. Vread can be different for each different verify voltage, or multiple verify voltages can be grouped for use with a common Vread.
    Type: Grant
    Filed: April 9, 2018
    Date of Patent: October 15, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Vinh Diep, Ching-Huang Lu, Zhengyi Zhang, Yingda Dong
  • Publication number: 20190311772
    Abstract: Apparatuses and techniques are described for programming memory cells with a narrow threshold voltage (Vth) distribution in a memory device. In one approach, the final pass of a multi-pass program operation on a word line WLn includes applying a variable voltage to WLn+1 during verify tests on WLn. The variable voltage (Vread) can be an increasing function of the verify voltage on WLn, and thus a function of the data state for which the verify test is performed. In one approach, Vread on WLn+1 is stepped up with each increase in the verify voltage on WLn. The step size in Vread can be the same as, or different than, the step size in the verify voltage. Vread can be different for each different verify voltage, or multiple verify voltages can be grouped for use with a common Vread.
    Type: Application
    Filed: April 9, 2018
    Publication date: October 10, 2019
    Applicant: SanDisk Technologies LLC
    Inventors: Vinh Diep, Ching-Huang Lu, Zhengyi Zhang, Yingda Dong
  • Patent number: 10438671
    Abstract: Techniques for reducing program disturb of memory cells which are formed in a two-tier stack, when a selected word line is in the upper tier. In one approach, at the start of the program phase of a program loop, voltages of word lines adjacent to the interface are increased to a pass voltage before voltages of remaining word lines are increased to a pass voltage. This delay provides time for residue electrons in the lower tier to move toward the drain end of a NAND string to reduce the likelihood of program disturb. In another approach, the voltages of the word lines adjacent to the interface are maintained at 0 V or other turn-off voltage during the program phase to block the passage of residue electrons from the lower tier to the upper tier.
    Type: Grant
    Filed: June 22, 2018
    Date of Patent: October 8, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Hong-Yan Chen, Yingda Dong
  • Publication number: 20190304987
    Abstract: A memory cell is provided that includes a control gate, a tunneling layer, a charge storage region, a blocking layer including a ferroelectric material, a semiconductor channel, and a source region and a drain region each disposed adjacent the semiconductor channel.
    Type: Application
    Filed: March 28, 2018
    Publication date: October 3, 2019
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Publication number: 20190304986
    Abstract: A non-volatile storage element including a control gate, a tunneling layer, a charge storage region, and a blocking layer including a ferroelectric material. The tunneling layer is disposed between the control gate and the charge storage region, and the charge storage region is disposed between the tunneling layer and the blocking layer.
    Type: Application
    Filed: March 28, 2018
    Publication date: October 3, 2019
    Applicant: SanDisk Technologies LLC
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Publication number: 20190304988
    Abstract: A non-volatile storage element is provided that includes a control gate, a blocking layer including a ferroelectric material, a charge storage region, and a tunneling layer. The blocking layer is disposed between the control gate and the charge storage region, and the charge storage region is disposed between the tunneling layer and the blocking layer.
    Type: Application
    Filed: March 28, 2018
    Publication date: October 3, 2019
    Applicant: SanDisk Technologies LLC
    Inventors: Yingda Dong, Yangyin Chen, Yukihiro Sakotsubo
  • Patent number: 10431313
    Abstract: A three-dimensional stacked memory device is configured to provide uniform programming speeds of different sets of memory strings formed in memory holes. In a process for removing sacrificial material from word line layers, a block oxide layer in the memory holes is etched away relatively more when the memory hole is relatively closer to an edge of the word line layers where an etchant is introduced. A thinner block oxide layer is associated with a faster programming speed. To compensate, memory strings at the edges of the word line layers are programmed together, separate from the programming of interior memory strings. A program operation can use a higher initial program voltage for programming the interior memory strings compared to the edge memory strings.
    Type: Grant
    Filed: March 16, 2018
    Date of Patent: October 1, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Zhengyi Zhang, Yingda Dong, James Kai, Johann Alsmeier
  • Patent number: 10424387
    Abstract: Apparatuses and techniques are described for programming a memory device with reduced temperature-based changes in the threshold voltage distribution (Vth). Different memory cells can have different values of a temperature coefficient, Tco, and high-Tco memory cells may tend to be at the lower tail of a Vth distribution. The memory cells are programmed using a first set of verify voltages which are temperature-independent. If the temperature at the time of the programming is less than a specified temperature, the high-Tco memory cells are identified and programmed further in a second pass using a second set of verify voltages which are temperature-dependent. Further, the second pass is configured to provide a narrower Vth distribution width than the first program pass. The second pass may use a smaller program pulse step size and/or an elevated bit line voltage.
    Type: Grant
    Filed: May 16, 2018
    Date of Patent: September 24, 2019
    Assignee: SanDisk Technologies LLC
    Inventors: Zhengyi Zhang, Yingda Dong
  • Patent number: 10373969
    Abstract: A method of operating a three-dimensional memory device includes applying a target string bias voltage to a selected drain select gate electrode which partially surrounds a row of memory stack structures that directly contact a drain select isolation structure, and applying a neighboring string bias voltage that has a greater magnitude than the target string bias voltage to an unselected drain select gate electrode that contacts the drain select level isolation structure.
    Type: Grant
    Filed: January 9, 2018
    Date of Patent: August 6, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yanli Zhang, Peng Zhang, Johann Alsmeier, Yingda Dong
  • Publication number: 20190221575
    Abstract: A three-dimensional memory device includes alternating stacks of insulating strips and electrically conductive strips laterally spaced apart among one another by line trenches and a two-dimensional array of memory stack structures and a two-dimensional array of dielectric pillar structures located in the line trenches. Each line trench is filled with laterally alternating sequence of memory stack structures and dielectric pillar structures. Each memory stack structure contains a vertical semiconductor channel, a pair of blocking dielectrics contacting outer sidewalls of the vertical semiconductor channel, a pair of charge storage layers contacting outer sidewalls of the pair of blocking dielectrics, and a pair of tunneling dielectrics contacting outer sidewalls of the pair of charge storage layers.
    Type: Application
    Filed: May 4, 2018
    Publication date: July 18, 2019
    Inventors: Yingda Dong, Yangyin Chen, James Kai
  • Patent number: 10355007
    Abstract: A memory stack structure includes a cavity including a back gate electrode, a back gate dielectric, a semiconductor channel, and at least one charge storage element. In one embodiment, a line trench can be filled with a memory film layer, and a plurality of semiconductor channels can straddle the line trench. The back gate electrode can extend along the lengthwise direction of the line trench. In another embodiment, an isolated memory opening overlying a patterned conductive layer can be filled with a memory film, and the back gate electrode can be formed within a semiconductor channel and on the patterned conductive layer. A dielectric cap portion electrically isolates the back gate electrode from a drain region. The back gate electrode can be employed to bias the semiconductor channel, and to enable sensing of multinary bits corresponding to different amounts of electrical charges stored in a memory cell.
    Type: Grant
    Filed: December 15, 2016
    Date of Patent: July 16, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiying Costa, Dana Lee, Yanli Zhang, Johann Alsmeier, Yingda Dong, Akira Matsudaira
  • Publication number: 20190214395
    Abstract: A method of operating a three-dimensional memory device includes applying a target string bias voltage to a selected drain select gate electrode which partially surrounds a row of memory stack structures that directly contact a drain select isolation structure, and applying a neighboring string bias voltage that has a greater magnitude than the target string bias voltage to an unselected drain select gate electrode that contacts the drain select level isolation structure.
    Type: Application
    Filed: January 9, 2018
    Publication date: July 11, 2019
    Inventors: Yanli Zhang, Peng Zhang, Johann Alsmeier, Yingda Dong