Patents by Inventor Anubhav Khandelwal
Anubhav Khandelwal 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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Publication number: 20240127891Abstract: Technology is disclosed herein in which a duration of a program pulse used to program non-volatile memory cells such as NAND may be increased responsive to a programming failure using a shorter duration program pulse. The duration of at least one program pulse may be increased for at least one group of memory cells in response to a failure to program a group using a default program pulse duration. The group that experiences the increased duration program pulse may be the same group for which the program operation failed using the shorter program pulse or may be a different group than the group for which the program operation failed using the shorter program pulse.Type: ApplicationFiled: July 21, 2023Publication date: April 18, 2024Applicant: SanDisk Technologies LLCInventors: Abu Naser Zainuddin, Parth Amin, Xiaochen Zhu, Jiahui Yuan, Anubhav Khandelwal, Vishwanath Basavaegowda Shanthakumar
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Publication number: 20230186993Abstract: The nonvolatile memory includes a plurality of nonvolatile memory cells configured to store multiple data states; a word line connected to a control gate of at least one of the plurality of non-volatile memory cells; a control gate line to supply a control gate signal; a word line switch connected between the word line and the control gate line to control the potential applied to the word line from the control gate line; and a memory controller circuit. The memory controller circuit is configured to control a word line potential on the word line and a control gate potential on the control gate line and to control a state of the control gate. The memory controller circuit, when the nonvolatile memory transitions to a not-on state, is further configured to turn off the word line switch and to charge the control gate line to a charged potential.Type: ApplicationFiled: February 14, 2023Publication date: June 15, 2023Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Patent number: 11605430Abstract: The nonvolatile memory includes a plurality of nonvolatile memory cells configured to store multiple data states; a word line connected to a control gate of at least one of the plurality of non-volatile memory cells; a control gate line to supply a control gate signal; a word line switch connected between the word line and the control gate line to control the potential applied to the word line from the control gate line; and a memory controller circuit. The memory controller circuit is configured to control a word line potential on the word line and a control gate potential on the control gate line and to control a state of the control gate. The memory controller circuit, when the nonvolatile memory transitions to a not-on state, is further configured to turn off the word line switch and to charge the control gate line to a charged potential.Type: GrantFiled: March 3, 2021Date of Patent: March 14, 2023Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Patent number: 11581049Abstract: Apparatus and methods are described to reduce program disturb for a memory string with a partial select gate drain, which is partially cut by a shallow trench. The memory string with a partial select gate drain is linked with a neighboring full select gate drain that during its programming can cause a program disturb in the memory string with a partial select gate drain. The bias voltage applied to the selected full select gate drain can be controlled from a high state for low memory program states to a lower state for the high memory program states. The high data states may cause program disturb. The reduction in the bias voltage can match a reduction in the bias voltage applied to the bit lines to reduce the program disturb while providing adequate signal to program the high states on the memory string of the full select gate drain.Type: GrantFiled: June 1, 2021Date of Patent: February 14, 2023Assignee: SanDisk Technologies LLCInventors: Kazuki Isozumi, Parth Amin, Sayako Nagamine, Anubhav Khandelwal
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Patent number: 11574693Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to one of a plurality of word lines and arranged in strings and configured to retain a threshold voltage corresponding to one of a plurality of memory states. A control circuit is coupled to the plurality of word lines and strings and is configured to erase the memory cells using a stripe erase operation in response to determining a cycle count is less than a predetermined cycle count maximum threshold. The control circuit is also configured to perform a dummy cycle operation in response to determining the cycle count is not less than the predetermined cycle count maximum threshold.Type: GrantFiled: June 15, 2021Date of Patent: February 7, 2023Assignee: SanDisk Technologies LLCInventors: Chin-Yi Chen, Muhammad Masuduzzaman, Dengtao Zhao, Anubhav Khandelwal, Ravi Kumar
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Patent number: 11562798Abstract: The programming techniques include the step of providing a memory device that includes a plurality of memory cells that are divided into at least two groups including a first group and a second group. The first group includes memory cells that are coupled to full select gate drains (SGDs), and the second group includes memory cells that are coupled to partial SGDs. The method continues with the step of applying a programming voltage to a selected word line that includes at least one memory cell of the first group and at least one memory cell of the second group. Simultaneous to the application of the programming voltage, the method continues with applying voltages to bit lines coupled to memory cells. The voltages being determined based on if the memory cells are of the first group or are of the second group.Type: GrantFiled: June 15, 2021Date of Patent: January 24, 2023Assignee: SanDisk Technologies LLCInventors: Parth Amin, Anubhav Khandelwal
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Patent number: 11545225Abstract: A method for detecting a “slow to erase” condition of a non-volatile memory structure, wherein the method comprises initiating an erase/verify memory operation with respect to the memory structure, wherein the erase/verify memory operation comprises applying an erase verify voltage according to an alternating word line scheme; following the erase/verify memory operation, determining if a first bit scan mode criteria is satisfied; and, if the first bit scan mode criteria is satisfied, initiating a read/verify memory operation wherein, the read/verify memory operation comprises applying a read-pass voltage according to an all word line scheme, and a magnitude of the read-pass voltage is greater than a magnitude of the erase verify voltage. Following the read/verify memory operation, the method also comprises determining if a second bit scan mode criteria is satisfied and, if the criteria is not satisfied, designating the memory structure with a fail status.Type: GrantFiled: June 24, 2021Date of Patent: January 3, 2023Assignee: SanDisk Technologies LLCInventors: Parth Amin, Anubhav Khandelwal
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Publication number: 20220415413Abstract: A method for detecting a “slow to erase” condition of a non-volatile memory structure, wherein the method comprises initiating an erase/verify memory operation with respect to the memory structure, wherein the erase/verify memory operation comprises applying an erase verify voltage according to an alternating word line scheme; following the erase/verify memory operation, determining if a first bit scan mode criteria is satisfied; and, if the first bit scan mode criteria is satisfied, initiating a read/verify memory operation wherein, the read/verify memory operation comprises applying a read-pass voltage according to an all word line scheme, and a magnitude of the read-pass voltage is greater than a magnitude of the erase verify voltage. Following the read/verify memory operation, the method also comprises determining if a second bit scan mode criteria is satisfied and, if the criteria is not satisfied, designating the memory structure with a fail status.Type: ApplicationFiled: June 24, 2021Publication date: December 29, 2022Applicant: SanDisk Technologies LLCInventors: Parth Amin, Anubhav Khandelwal
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Publication number: 20220399066Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to one of a plurality of word lines and arranged in strings and configured to retain a threshold voltage corresponding to one of a plurality of memory states. A control circuit is coupled to the plurality of word lines and strings and is configured to erase the memory cells using a stripe erase operation in response to determining a cycle count is less than a predetermined cycle count maximum threshold. The control circuit is also configured to perform a dummy cycle operation in response to determining the cycle count is not less than the predetermined cycle count maximum threshold.Type: ApplicationFiled: June 15, 2021Publication date: December 15, 2022Applicant: SanDisk Technologies LLCInventors: Chin-Yi Chen, Muhammad Masuduzzaman, Dengtao Zhao, Anubhav Khandelwal, Ravi Kumar
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Publication number: 20220399063Abstract: The programming techniques include the step of providing a memory device that includes a plurality of memory cells that are divided into at least two groups including a first group and a second group. The first group includes memory cells that are coupled to full select gate drains (SGDs), and the second group includes memory cells that are coupled to partial SGDs. The method continues with the step of applying a programming voltage to a selected word line that includes at least one memory cell of the first group and at least one memory cell of the second group. Simultaneous to the application of the programming voltage, the method continues with applying voltages to bit lines coupled to memory cells. The voltages being determined based on if the memory cells are of the first group or are of the second group.Type: ApplicationFiled: June 15, 2021Publication date: December 15, 2022Applicant: SanDisk Technologies LLCInventors: Parth Amin, Anubhav Khandelwal
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Publication number: 20220399058Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and arranged in strings and configured to retain a threshold voltage corresponding to memory states. A control circuit is configured to program the memory cells to reach one of a plurality of verify levels each corresponding the memory states using a series of voltage pulses applied to the word lines during a program operation. The control circuit determines an intermediate quantity of the series of voltage pulses necessary for the memory cells associated with a selected one of the memory states to reach the one of the plurality of verify levels corresponding to the selected one of the memory states. The control circuit ends the program operation after a maximum allowable quantity of the series of voltage pulses are utilized. The maximum allowable quantity is selected based on the intermediate quantity.Type: ApplicationFiled: June 9, 2021Publication date: December 15, 2022Applicant: SanDisk Technologies LLCInventors: Parth Amin, Anubhav Khandelwal
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Publication number: 20220383967Abstract: Apparatus and methods are described to reduce program disturb for a memory string with a partial select gate drain, which is partially cut by a shallow trench. The memory string with a partial select gate drain is linked with a neighboring full select gate drain that during its programming can casuse a program disturb in the memory string with a partial select gate drain. The bias voltage applied to the selected full select gate drain can be controlled from a high state for low memory program states to a lower state for the high memory program states. The high data states may cause program disturb. The reduction in the bias voltage can match a reduction in the bias voltage applied to the bit lines to reduce the program disturb while providing adequate signal to program the high states on the memory string of the full select gate drain.Type: ApplicationFiled: June 1, 2021Publication date: December 1, 2022Applicant: SanDisk Technologies LLCInventors: Kazuki Isozumi, Parth Amin, Sayako Nagamine, Anubhav Khandelwal
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Patent number: 11482289Abstract: A memory apparatus and method of operation are provided. The apparatus includes a plurality of memory cells. Each of the plurality of memory cells is connected to one of a plurality of word lines and is arranged in one of a plurality of blocks. Each of the plurality of memory cells is configured to retain a threshold voltage corresponding to one of a plurality of data states. A control circuit is coupled to the plurality of word lines and is configured to detect at least one use characteristic of the memory apparatus. The control circuit adjusts a verify voltage level by one of a plurality of verify level offsets based on the at least one use characteristic that is detected. The verify voltage level is applied to the one of the plurality of word lines selected for programming following an application of a program voltage during a program operation.Type: GrantFiled: March 4, 2021Date of Patent: October 25, 2022Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Publication number: 20220336019Abstract: An apparatus that includes a word line with a plurality of memory cells that are able to be programmed to a plurality of data states is provided. The apparatus further includes a programming circuit. The programming circuit is configured to program the memory cells and count the number of verify pulses at a first verify voltage level that are performed during programming of the memory cells to a first programmed data state to determine a verify count. During programming to a second data state, the programming circuit applies a plurality of programming pulses at increasing voltage levels and a plurality of verify pulses at a second verify voltage level to the selected word line. During programming of the memory cells to the second programmed data state, the number of verify pulses is one fewer than the number of programming pulses and bitscan operations are skipped.Type: ApplicationFiled: April 15, 2021Publication date: October 20, 2022Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Patent number: 11468950Abstract: An apparatus that includes a word line with a plurality of memory cells that are able to be programmed to a plurality of data states is provided. The apparatus further includes a programming circuit. The programming circuit is configured to program the memory cells and count the number of verify pulses at a first verify voltage level that are performed during programming of the memory cells to a first programmed data state to determine a verify count. During programming to a second data state, the programming circuit applies a plurality of programming pulses at increasing voltage levels and a plurality of verify pulses at a second verify voltage level to the selected word line. During programming of the memory cells to the second programmed data state, the number of verify pulses is one fewer than the number of programming pulses and bitscan operations are skipped.Type: GrantFiled: April 15, 2021Date of Patent: October 11, 2022Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Patent number: 11450393Abstract: A non-volatile memory apparatus and method of operation are provided. The apparatus includes storage elements connected to a word line. Each of the storage elements is configured to be programmed to a respective target data state. The apparatus also includes a respective bit line associated with each of the storage elements and a control circuit configured to apply a plurality of program pulses to the word line that progressively increase by a program step voltage. The control circuit counts an over programming number of the storage elements having a threshold voltage exceeding an over programming verify level of the respective target data state that is less than a default verify level and based on the program step voltage. The control circuit adjusts a voltage of the respective bit line to one or more adjusted levels in response to the over programming number being greater than a predetermined over programming number.Type: GrantFiled: March 9, 2021Date of Patent: September 20, 2022Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Publication number: 20220293197Abstract: A non-volatile memory apparatus and method of operation are provided. The apparatus includes storage elements connected to a word line. Each of the storage elements is configured to be programmed to a respective target data state. The apparatus also includes a respective bit line associated with each of the storage elements and a control circuit configured to apply a plurality of program pulses to the word line that progressively increase by a program step voltage. The control circuit counts an over programming number of the storage elements having a threshold voltage exceeding an over programming verify level of the respective target data state that is less than a default verify level and based on the program step voltage. The control circuit adjusts a voltage of the respective bit line to one or more adjusted levels in response to the over programming number being greater than a predetermined over programming number.Type: ApplicationFiled: March 9, 2021Publication date: September 15, 2022Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Publication number: 20220284961Abstract: The nonvolatile memory includes a plurality of nonvolatile memory cells configured to store multiple data states; a word line connected to a control gate of at least one of the plurality of non-volatile memory cells; a control gate line to supply a control gate signal; a word line switch connected between the word line and the control gate line to control the potential applied to the word line from the control gate line; and a memory controller circuit. The memory controller circuit is configured to control a word line potential on the word line and a control gate potential on the control gate line and to control a state of the control gate. The memory controller circuit, when the nonvolatile memory transitions to a not-on state, is further configured to turn off the word line switch and to charge the control gate line to a charged potential.Type: ApplicationFiled: March 3, 2021Publication date: September 8, 2022Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Publication number: 20220284971Abstract: A memory apparatus and method of operation are provided. The apparatus includes a plurality of memory cells. Each of the plurality of memory cells is connected to one of a plurality of word lines and is arranged in one of a plurality of blocks. Each of the plurality of memory cells is configured to retain a threshold voltage corresponding to one of a plurality of data states. A control circuit is coupled to the plurality of word lines and is configured to detect at least one use characteristic of the memory apparatus. The control circuit adjusts a verify voltage level by one of a plurality of verify level offsets based on the at least one use characteristic that is detected. The verify voltage level is applied to the one of the plurality of word lines selected for programming following an application of a program voltage during a program operation.Type: ApplicationFiled: March 4, 2021Publication date: September 8, 2022Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal
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Patent number: 11410739Abstract: An apparatus that includes a word line with a plurality of memory cells that are able to be programmed to a plurality of data states is provided. The apparatus further includes a programming circuit. The programming circuit is configured to program count the number of verify pulses at a first verify voltage level that are performed during programming of the memory cells to a first programmed data state to determine a verify count. During programming to a second data state, the programming circuit applies a plurality of programming pulses at increasing voltage levels and a plurality of verify pulses at a second verify voltage level to the selected word line. During programming of the memory cells to the second programmed data state, the number of verify pulses is one fewer than the number of programming pulses.Type: GrantFiled: March 19, 2021Date of Patent: August 9, 2022Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Anubhav Khandelwal