Patents Assigned to SanDisk Technologies LLC
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Patent number: 10431313Abstract: 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: GrantFiled: March 16, 2018Date of Patent: October 1, 2019Assignee: SanDisk Technologies LLCInventors: Zhengyi Zhang, Yingda Dong, James Kai, Johann Alsmeier
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Publication number: 20190296723Abstract: A skew correction system includes delay circuits positioned in front of sampling circuitry. A skew correction controller first delays an input clock signal to create hold violations. Then with, with the delay of an input clock signal fixed at a reference delay amount, the skew correction controller delays input data signals first to remove or reduce the hold violations, and then to create setup violations. Based on the delaying, the skew correction controller identifies data valid windows for the input data signals, and in turn, identifies target delay amounts that position a delayed clock signal in target sampling positions.Type: ApplicationFiled: June 25, 2018Publication date: September 26, 2019Applicant: SanDisk Technologies LLCInventors: Tianyu Tang, Venkatesh Ramachandra
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Publication number: 20190295669Abstract: A circuit includes a detection circuit configured to determine a capacitance delay (RC-delay) in an initial stage of a read or program operation and to adjust timing for detecting data in a subsequent stage, or portion of a stage, of the same read or programing operation. In particular, during a program operation a detection circuit may be configured to detect a pre-charge time for a bit line and adjust a timing of subsequent verify stages of the bit line during the same program operation based on the detected pre-charge time. Additionally, a word line circuit may be configured to detect a pre-charge time for a word line during an initial stage of a read operation and adjust read timing for a subsequent portion of the same read stage, or subsequent read stage of the read operation based on the detected word line pre-charge time.Type: ApplicationFiled: March 22, 2018Publication date: September 26, 2019Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Piyush Dak, Wei Zhao, Huai-Yuan Tseng, Deepanshu Dutta, Mohan Dunga
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Patent number: 10424387Abstract: 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: GrantFiled: May 16, 2018Date of Patent: September 24, 2019Assignee: SanDisk Technologies LLCInventors: Zhengyi Zhang, Yingda Dong
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Publication number: 20190272871Abstract: Apparatuses, systems, and methods are disclosed for adjusting a programming setting such as a programming voltage of a set of non-volatile storage cells, such as an SLC NAND array. The non-volatile storage cells may be arranged into a plurality of word lines. A subset of the non-volatile storage cells may be configured to store a programming setting. An on-die controller may be configured to read the programming setting from the setting subset, and write data to the non-volatile storage cells, using the programming setting. The on-die controller may further be configured to determine that the programming setting causes suboptimal programming of one or more of the non-volatile storage cells, and in response to the determination, store a revised programming setting on the setting subset.Type: ApplicationFiled: March 2, 2018Publication date: September 5, 2019Applicant: SanDIsk Technologies LLCInventors: Xiang Yang, Huai-Yuan Tseng, Deepanshu Dutta
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Patent number: 10402313Abstract: In order to write data to a storage system accessible with a first and second file system, a manager receives a data write request associated with a file. The manager determines if a function supported by the second file system is needed to complete the write request. If so, the file is opened and extended with the first file system. The file is then opened and written to by the second file system. The file is truncated by the first file system, and closed by both file systems. If the second file system function is not needed, the file is opened, written, and closed by the first file system. In order to read data from a storage system using a function supported by the second file system, the second file system's cached storage system index is updated, and then the file is opened, read, and closed by the second file system.Type: GrantFiled: April 15, 2013Date of Patent: September 3, 2019Assignee: SanDisk Technologies LLCInventors: Junzhi Wang, Alon Marcu, Ori Stern, Susan A. Cannon, Xian Jun Liu, Chieh-Hao Yang, Po Yuan
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Publication number: 20190267096Abstract: A circuit includes selected sense circuits configured to be connected to selected bit lines and unselected sense circuits configured to be connected to unselected bit lines during a sense operation. When the sense circuit is connected to the unselected bit line during the sense operation, the sense circuit is locked out in order to reduce current consumption. However, noise from the locked out sense circuit may be transmitted to the sense circuits connected to the selected bit lines through adjacent bit line coupling. In order to reduce the effect of the noise, charge transfer from the sense node may be blocked from passing to the unselected bit lines. Or, charge may be drained from the sense node, thereby preventing the charge from passing to the unselected bit lines.Type: ApplicationFiled: February 28, 2018Publication date: August 29, 2019Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Stanley Jeong, Wei Zhao, Huai-yuan Tseng, Deepanshu Dutta
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Publication number: 20190267082Abstract: In a memory system, variable resistance circuits, such as transistor circuits, in the word line and bit line decoders are set during bias line set times and/or prior to turn-on times of read operations to increased resistance levels. The variable resistance circuits are kept at the increased resistance levels during an initial turn-on time period during which a selected memory cell may conducts a current spike. The increased resistance levels of the variable resistance circuit may operate to reduce or limit the width of the current spike. In response to the initial turn-on time period ending, the variable resistance circuits are set back to low resistance levels to facilitate subsequent sense results detection events and program operations.Type: ApplicationFiled: February 28, 2018Publication date: August 29, 2019Applicant: SanDisk Technologies LLCInventors: Ward Parkinson, Thomas Michael Trent, James Edwin O'Toole
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Patent number: 10394649Abstract: Techniques are provided for improving the accuracy of read operations of memory cells, where the threshold voltage of a memory cell can shift depending on when the read operation occurs. A memory cell is sensed by discharging a sense node into a bit line and detecting an amount of discharge at two sense times relative to a trip voltage. A bit of data is stored in first and second latches based on the two sense times, to provide first and second pages of data. The pages are evaluated using parity check equations and one of the pages which satisfies the most equations is selected. In another option, word line voltages are grounded and then floated to prevent coupling up of the word line. A weak pulldown to ground can gradually discharge a coupled up voltage of the word lines.Type: GrantFiled: March 14, 2018Date of Patent: August 27, 2019Assignee: SanDisk Technologies LLCInventors: Idan Alrod, Eran Sharon, Alon Eyal, Liang Pang, Evgeny Mekhanik
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Publication number: 20190259462Abstract: Apparatuses and techniques are described for reducing charge loss in a select gate transistor in a memory device. In one aspect, a refresh operation is performed repeatedly to couple up data word line voltages but not dummy word line voltages. The refresh operation can involve applying a voltage pulse to the data word lines of a block when the block is not being used for a storage operation such as a program, read or erase operation. When the voltage pulse is applied to the data word lines, the dummy word lines can be set to a low level such as 0 V. This low level prevents or limits coupling up of the dummy memory cells to avoid creating an electric field which can cause holes to move from the dummy memory cells to adjacent select gate transistors.Type: ApplicationFiled: February 20, 2018Publication date: August 22, 2019Applicant: SanDisk Technologies LLCInventors: Ching-Huang Lu, Vinh Diep
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Patent number: 10388870Abstract: Systems and methods for reducing leakage currents through unselected memory cells of a memory array including setting an adjustable resistance bit line structure connected to the unselected memory cells into a high resistance state or a non-conducting state during a memory operation are described. The adjustable resistance bit line structure may comprise a bit line structure in which the resistance of an intrinsic (or near intrinsic) polysilicon portion of the bit line structure may be adjusted via an application of a voltage to a select gate portion of the bit line structure that is electrically isolated from the intrinsic polysilicon portion (e.g., via an oxide layer between the intrinsic polysilicon portion and the select gate portion). The memory cells may comprise a first conductive metal oxide (e.g., titanium oxide) that abuts a second conductive metal oxide (e.g., aluminum oxide) that abuts a layer of amorphous silicon.Type: GrantFiled: October 25, 2017Date of Patent: August 20, 2019Assignee: SanDisk Technologies LLCInventors: Perumal Ratnam, Tanmay Kumar, Christopher Petti
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Patent number: 10388390Abstract: Sensing in non-volatile memory is performed using bias conditions that are dependent on the position of a selected memory cell within a group of non-volatile memory cells. During sensing, a selected memory cell receives a reference voltage while the remaining memory cells receive a read or verify pass voltage. For at least a subset of the unselected memory cells, the pass voltage that is applied is dependent upon the position of the selected memory cell in the group. As programming progresses from a memory cell at a first end of a NAND string toward a memory cell at a second end of the NAND string, for example, the pass voltage for at least a subset of the unselected memory cells that have already been subjected to programming may be increased. This technique may reduce the effects of an increased channel resistance that occurs as more memory cells are programmed.Type: GrantFiled: March 21, 2019Date of Patent: August 20, 2019Assignee: SanDisk Technologies LLCInventor: Xiying Costa
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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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Publication number: 20190251067Abstract: Apparatuses, systems, and methods are disclosed for snapshots of a non-volatile device. A method includes writing data in a sequential log structure for a non-volatile device. A method includes marking a point, in a sequential log structure, for a snapshot of data. A method includes preserving a logical-to-physical mapping for a snapshot based on a marked point and a temporal order for data in a sequential log structure.Type: ApplicationFiled: April 25, 2019Publication date: August 15, 2019Applicant: SanDisk Technologies LLCInventors: Nisha Talagala, Swaminathan Sundararaman, Sriram Subramanian
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Patent number: 10381548Abstract: Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction for storing data may include a reference layer, a barrier layer, and a free layer. A barrier layer may be disposed between a reference layer and a free layer. A free layer may include a nucleation region and an arm. A nucleation region may be configured to form a magnetic domain wall. An arm may be narrower than a nucleation region and may extend from the nucleation region. An arm may include a plurality of pinning sites formed at predetermined locations along the arm for pinning a domain wall.Type: GrantFiled: February 8, 2018Date of Patent: August 13, 2019Assignee: SanDisk Technologies LLCInventors: Young-Suk Choi, Won Ho Choi
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Patent number: 10381083Abstract: A memory device and associated techniques avoid a disturb of a select gate transistor during an erase operation for memory cells in a string. During the erase operation, a channel potential gradient near the select gate transistors is reduced when the voltages of the bit line and the substrate are suitably controlled. In one approach, the voltage of the substrate at a source end of the memory string is increased to an intermediate level first before being increased to the erase voltage threshold level while the voltage of the bit line is held at a reference voltage level to delay floating the voltage of the bit line. Another approach builds off the first approach by temporarily decreasing the voltage of the bit line to a negative level before letting the voltage of the bit line to float at the same time as the voltage of the substrate is increased to the erase voltage threshold level.Type: GrantFiled: June 25, 2018Date of Patent: August 13, 2019Assignee: SanDisk Technologies LLCInventors: Xiang Yang, Kun-Huan Shih, Matthias Baenninger, Huai-Yuan Tseng, Dengtao Zhao, Deepanshu Dutta
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Patent number: 10381327Abstract: A non-volatile storage system includes a plurality of memory dies and an interface circuit. Each memory die includes a wide I/O interface electrically coupled to another wide I/O interface of another memory die of the plurality of memory dies. The interface circuit is physically separate from the memory dies. The interface circuit includes a first interface and a second interface. The first interface comprises a wide I/O interface electrically coupled to a wide I/O interface of at least one of the memory dies of the plurality of memory dies. The second interface is a narrow I/O interface configured to communicate with an external circuit.Type: GrantFiled: October 6, 2016Date of Patent: August 13, 2019Assignee: SanDisk Technologies LLCInventors: Venkatesh P. Ramachandra, Michael Mostovoy, Hem Takiar, Gokul Kumar, Vinayak Ghatawade
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Patent number: 10381559Abstract: Alternating stacks of insulating strips and sacrificial material strips are formed over a substrate. A laterally alternating sequence of pillar cavities and pillar structures can be formed within each of the line trenches. A phase change memory cell including a discrete metal portion, a phase change memory material portion, and a selector material portion is formed at each level of the sacrificial material strips at a periphery of each of the pillar cavities. Vertical bit lines are formed in the two-dimensional array of pillar cavities. Remaining portions of the sacrificial material strips are replaced with electrically conductive word line strips. Pathways for providing an isotropic etchant for the sacrificial material strips and a reactant for a conductive material of the electrically conductive word line strips may be provided by a backside trench, or by removing the pillar structures to provide backside openings.Type: GrantFiled: June 7, 2018Date of Patent: August 13, 2019Assignee: SanDisk Technologies LLCInventors: Fei Zhou, Raghuveer S. Makala, Christopher J. Petti, Rahul Sharangpani, Adarsh Rajashekhar, Seung-Yeul Yang
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Patent number: 10381095Abstract: In order to have different subsets of memory cells of a non-volatile memory system erase at the same speed, it is proposed to perform erasing by separately controlling the speed of erase for the different subsets in response to observing speed information for the subsets during the erasing.Type: GrantFiled: February 28, 2018Date of Patent: August 13, 2019Assignee: SanDisk Technologies LLCInventors: Kei Date, Hideto Tomiie
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Publication number: 20190245136Abstract: Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction for storing data may include a reference layer, a barrier layer, and a free layer. A barrier layer may be disposed between a reference layer and a free layer. A free layer may include a nucleation region and an arm. A nucleation region may be configured to form a magnetic domain wall. An arm may be narrower than a nucleation region and may extend from the nucleation region. An arm may include a plurality of pinning sites formed at predetermined locations along the arm for pinning a domain wall.Type: ApplicationFiled: February 8, 2018Publication date: August 8, 2019Applicant: SanDisk Technologies LLCInventors: YOUNG-SUK CHOI, WON HO CHOI