Patents by Inventor Rajdeep Gautam
Rajdeep Gautam 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: 11889694Abstract: A memory die includes an alternating stack of insulating layers and electrically conductive layers through which memory opening fill structures vertically extend. The memory die includes at least three memory array regions interlaced with at least two contact regions, or at least three contact regions interlaced with at least two memory array regions in the same memory plane. A logic die including at least two word line driver regions can be bonded to the memory die. The interlacing of the contact regions and the memory array regions can reduce lateral offset of boundaries of the word line driver regions from boundaries of the contact regions.Type: GrantFiled: August 9, 2021Date of Patent: January 30, 2024Assignee: SANDISK TECHNOLOGIES LLCInventors: Hardwell Chibvongodze, Zhixin Cui, Rajdeep Gautam, Hiroyuki Ogawa
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Publication number: 20230041950Abstract: A memory die includes an alternating stack of insulating layers and electrically conductive layers through which memory opening fill structures vertically extend. The memory die includes at least three memory array regions interlaced with at least two contact regions, or at least three contact regions interlaced with at least two memory array regions in the same memory plane. A logic die including at least two word line driver regions can be bonded to the memory die. The interlacing of the contact regions and the memory array regions can reduce lateral offset of boundaries of the word line driver regions from boundaries of the contact regions.Type: ApplicationFiled: August 9, 2021Publication date: February 9, 2023Inventors: Hardwell Chibvongodze, Zhixin Cui, Rajdeep Gautam, Hiroyuki Ogawa
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Publication number: 20230038557Abstract: A memory die includes an alternating stack of insulating layers and electrically conductive layers through which memory opening fill structures vertically extend. The memory die includes at least three memory array regions interlaced with at least two contact regions, or at least three contact regions interlaced with at least two memory array regions in the same memory plane. A logic die including at least two word line driver regions can be bonded to the memory die. The interlacing of the contact regions and the memory array regions can reduce lateral offset of boundaries of the word line driver regions from boundaries of the contact regions.Type: ApplicationFiled: August 9, 2021Publication date: February 9, 2023Inventors: Hiroyuki Ogawa, Hardwell Chibvongodze, Zhixin Cui, Rajdeep Gautam
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Read and verify methodology and structure to counter gate SiOdependence of non-volatile memory cells
Patent number: 11551768Abstract: A method for programming a target memory cell in a memory array of a non-volatile memory system, the method comprising defining a default read biasing voltage value and a default verify biasing voltage value for each program state of a target memory cell of a memory structure, determining a location of a target memory cell within the memory structure and, based upon the determined location of the target memory cell, applying a first incremental offset voltage to the default read biasing voltage value with respect to each program state, and applying a second incremental offset voltage to the default verify biasing voltage value with respect to each program state.Type: GrantFiled: November 6, 2020Date of Patent: January 10, 2023Assignee: SanDisk Technologies LLCInventors: Rajdeep Gautam, Akira Okada -
Patent number: 11361816Abstract: Apparatuses and techniques are described for providing separate source regions in the substrate below a block of memory cells. The source regions can be separately driven by respective voltage drivers to provide benefits such as more uniform program and erase speeds and narrower threshold voltage distributions. In one approach, a single source region is provided and divided into multiple source regions by etching trenches and filling the trenches with an insulating material. Contacts to the source regions can include post-shaped contacts which extend through the block for each source region. In another approach, one or more planar contacts extend through the block for each source region. In another aspect, a program operation applies different voltages to the respective source regions during a verify test of a program operation.Type: GrantFiled: August 18, 2020Date of Patent: June 14, 2022Assignee: SanDisk Technologies LLCInventors: Zhixin Cui, Rajdeep Gautam, Hardwell Chibvongodze
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Patent number: 11335671Abstract: Multiple bonded units are provided, each of which includes a respective front-side die and a backside die. The two dies in each bonded unit may be a memory die and a logic die configured to control operation of memory elements in the memory die. Alternatively, the two dies may be memory dies. The multiple bonded units can be attached such that front-side external bonding pads have physically exposed surfaces that face upward and backside external bonding pads of each bonded unit have physically exposed surfaces that face downward. A first set of bonding wires can connect a respective pair of front-side external bonding pads, and a second set of bonding wires can connect a respective pair of backside external bonding pads.Type: GrantFiled: May 28, 2020Date of Patent: May 17, 2022Assignee: SANDISK TECHNOLOGIES LLCInventors: Hardwell Chibvongodze, Zhixin Cui, Rajdeep Gautam
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Publication number: 20220148665Abstract: A method for programming a target memory cell in a memory array of a non-volatile memory system, the method comprising defining a default read biasing voltage value and a default verify biasing voltage value for each program state of a target memory cell of a memory structure, determining a location of a target memory cell within the memory structure and, based upon the determined location of the target memory cell, applying a first incremental offset voltage to the default read biasing voltage value with respect to each program state, and applying a second incremental offset voltage to the default verify biasing voltage value with respect to each program state.Type: ApplicationFiled: November 6, 2020Publication date: May 12, 2022Applicant: SanDisk Technologies LLCInventors: Rajdeep Gautam, Akira Okada
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Publication number: 20220059157Abstract: Apparatuses and techniques are described for providing separate source regions in the substrate below a block of memory cells. The source regions can be separately driven by respective voltage drivers to provide benefits such as more uniform program and erase speeds and narrower threshold voltage distributions. In one approach, a single source region is provided and divided into multiple source regions by etching trenches and filling the trenches with an insulating material. Contacts to the source regions can include post-shaped contacts which extend through the block for each source region. In another approach, one or more planar contacts extend through the block for each source region.Type: ApplicationFiled: August 18, 2020Publication date: February 24, 2022Applicant: SanDisk Technologies LLCInventors: Zhixin Cui, Rajdeep Gautam, Hardwell Chibvongodze
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Publication number: 20210375847Abstract: Multiple bonded units are provided, each of which includes a respective front-side die and a backside die. The two dies in each bonded unit may be a memory die and a logic die configured to control operation of memory elements in the memory die. Alternatively, the two dies may be memory dies. The multiple bonded units can be attached such that front-side external bonding pads have physically exposed surfaces that face upward and backside external bonding pads of each bonded unit have physically exposed surfaces that face downward. A first set of bonding wires can connect a respective pair of front-side external bonding pads, and a second set of bonding wires can connect a respective pair of backside external bonding pads.Type: ApplicationFiled: May 28, 2020Publication date: December 2, 2021Inventors: Hardwell CHIBVONGODZE, Zhixin CUI, Rajdeep GAUTAM
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Patent number: 11069410Abstract: First alternating stacks of first insulating strips and first spacer material strips is formed in a first device region, second alternating stacks of second insulating strips and second spacer material strips are formed in a second device region. Each of the first line trenches is filled with a respective laterally alternating sequence of memory stack structures and first dielectric pillar structures to form a three-dimensional NAND memory. Each of the memory stack structures includes a vertical semiconductor channel and a vertical stack of memory elements. Each of the second line trenches with a respective laterally alternating sequence of active region assemblies of lateral field effect transistors and second dielectric pillar structures to form a three-dimensional NOR memory. Each of the active region assemblies includes a source pillar, a drain pillar, and a tubular channel region. The spacer material strips include, or are subsequently replaced with, electrically conductive strips.Type: GrantFiled: August 5, 2020Date of Patent: July 20, 2021Assignee: SANDISK TECHNOLOGIES LLCInventors: Zhixin Cui, Hardwell Chibvongodze, Rajdeep Gautam
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Patent number: 11049580Abstract: Systems and methods for increasing cycling endurance and minimizing over programming of non-volatile memory cells by modulating the programming voltage applied to the non-volatile memory cells over time as the number of program/erase cycles increases are described. A bit count ratio based on bit counts within two threshold voltage zones may be used to determine the amount of voltage reduction in the programming voltage applied during subsequent programming operations. For example, if the bit count ratio is between 0.02 and 0.05, then the reduction in the programming voltage may be 100 mV; if the bit count ratio is between 0.05 and 0.10, then the reduction in the programming voltage may be 200 mV. The modulation (e.g., the reduction) of the programming voltage may be performed at varying cycle intervals depending on the total number of program/erase cycles for a memory block and/or the bit count ratio.Type: GrantFiled: June 28, 2020Date of Patent: June 29, 2021Assignee: SANDISK TECHNOLOGIES LLCInventors: Rajdeep Gautam, Ken Oowada
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Patent number: 11004525Abstract: Systems and methods for increasing cycling endurance and minimizing over programming of non-volatile memory cells by modulating the programming voltage applied to the non-volatile memory cells over time as the number of program/erase cycles increases are described. A bit count ratio based on bit counts within two threshold voltage zones may be used to determine the amount of voltage reduction in the programming voltage applied during subsequent programming operations. For example, if the bit count ratio is between 0.02 and 0.05, then the reduction in the programming voltage may be 100 mV; if the bit count ratio is between 0.05 and 0.10, then the reduction in the programming voltage may be 200 mV. The modulation (e.g., the reduction) of the programming voltage may be performed at varying cycle intervals depending on the total number of program/erase cycles for a memory block and/or the bit count ratio.Type: GrantFiled: February 20, 2020Date of Patent: May 11, 2021Assignee: SANDISK TECHNOLOGIES LLCInventors: Rajdeep Gautam, Ken Oowada
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Patent number: 10978152Abstract: Systems and methods for reducing program disturb when programming portions of a memory array are described. A memory array may include a first set of NAND strings and a second set of NAND strings that share a common bit line that is connected to the drain-side end of drain-side select gates of the NAND strings and/or share a common source-side select gate line that connects to the gates of source-side select gates of the NAND strings. During programming of the first set of NAND strings a first pass voltage (e.g., 7V) may be applied to unselected word lines of the memory array and subsequently during programming of the second set of NAND strings a second pass voltage (e.g., 9V) greater than the first pass voltage may be applied to the unselected word lines of the memory array.Type: GrantFiled: November 13, 2019Date of Patent: April 13, 2021Assignee: SANDISK TECHNOLOGIES LLCInventors: Rajdeep Gautam, Hardwell Chibvongodze, Ken Oowada
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Patent number: 10971231Abstract: Systems and methods for reducing program disturb when programming portions of a memory array are described. A memory array may include a first set of NAND strings and a second set of NAND strings that share a common bit line that is connected to the drain-side end of drain-side select gates of the NAND strings and/or share a common source-side select gate line that connects to the gates of source-side select gates of the NAND strings. During programming of the first set of NAND strings a first pass voltage (e.g., 7V) may be applied to unselected word lines of the memory array and subsequently during programming of the second set of NAND strings a second pass voltage (e.g., 9V) greater than the first pass voltage may be applied to the unselected word lines of the memory array.Type: GrantFiled: June 26, 2020Date of Patent: April 6, 2021Assignee: SANDISK TECHNOLOGIES LLCInventors: Rajdeep Gautam, Hardwell Chibvongodze, Ken Oowada
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Publication number: 20190252029Abstract: Apparatuses and techniques are described for reducing charge loss in a select gate transistor in a memory device. In one aspect, a dummy memory cell adjacent to a select gate transistor is weakly programmed during an erase operation by applying a program pulse to the dummy memory cell. The program pulse can be applied after an erase bias is applied to the memory cells and before an erase-verify test is performed, in one approach. The program pulse can be applied during the setup of the voltages for the erase-verify test. The magnitude of the program pulse can be increased in successive erase loops of an erase operation as the magnitude of a substrate voltage is also increased. The magnitude of the program pulse can also be set as an increasing function of a number of program-erase (P-E) cycles.Type: ApplicationFiled: February 15, 2018Publication date: August 15, 2019Applicant: SanDisk Technologies LLCInventors: Chun-Hung Lai, Rajdeep Gautam, Ching-Huang Lu, Shih-Chung Lee
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Patent number: 10373697Abstract: Apparatuses and techniques are described for reducing charge loss in a select gate transistor in a memory device. In one aspect, a dummy memory cell adjacent to a select gate transistor is weakly programmed during an erase operation by applying a program pulse to the dummy memory cell. The program pulse can be applied after an erase bias is applied to the memory cells and before an erase-verify test is performed, in one approach. The program pulse can be applied during the setup of the voltages for the erase-verify test. The magnitude of the program pulse can be increased in successive erase loops of an erase operation as the magnitude of a substrate voltage is also increased. The magnitude of the program pulse can also be set as an increasing function of a number of program-erase (P-E) cycles.Type: GrantFiled: February 15, 2018Date of Patent: August 6, 2019Assignee: SanDisk Technologies LLCInventors: Chun-Hung Lai, Rajdeep Gautam, Ching-Huang Lu, Shih-Chung Lee