Abstract: Non-volatile storage systems, and methods for programming non-volatile storage elements of non-volatile storage systems, are described herein. A method for programming a non-volatile storage element, wherein a loop number is incremented with each program-verify iteration includes performing a plurality of program-verify iterations for the non-volatile storage element. This includes inhibiting programming of the non-volatile storage element when the loop number is less than a loop number threshold corresponding to a target data state that the storage element is being programmed to. This also includes enabling programming of the non-volatile storage element when the the loop number is greater than or equal to the loop number threshold corresponding to the target data state that the storage element is being programmed to.
Type:
Grant
Filed:
September 22, 2014
Date of Patent:
April 11, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Anubhav Khandelwal, Dana Lee, Henry Chin, LanLan Gu
Abstract: Three-dimensional (3D) non-volatile memory arrays having a vertically-oriented thin film transistor (TFT) select device and methods of fabricating such a memory are described. The vertically-oriented TFT may be used as a vertical bit line selection device to couple a global bit line to a vertical bit line. A select device pillar includes a body and upper and lower source/drain regions. At least one gate is separated horizontally from the select device pillar by a gate dielectric. The gates overlie the global bit lines with one or more insulating layers therebetween to provide adequate isolation between the gates and the global bit lines. Processes for fabricating the vertical TFT select devices utilize a gate dielectric and optional dielectric bases to provide isolation between the gates and bit lines.
Type:
Application
Filed:
December 15, 2016
Publication date:
April 6, 2017
Applicant:
SanDisk Technologies LLC
Inventors:
Michael Konevecki, Steve Radigan, Vance Dunton, Natalie Nguyen, Luke Zhang
Abstract: In one embodiment, a memory system is provided comprising a volatile memory, a non-volatile memory, and an error correction code (ECC) module. The ECC module is configured to encode, decode, and correct data stored in the volatile memory when the memory system enters and exits a sleep mode and is further configured to encode, decode, and correct data stored in the non-volatile memory when the memory system is in an active mode.
Abstract: A virtual machine cache provides for maintaining a working set of the cache during a transfer between virtual machine hosts. In response to the transfer, a previous host retains cache data of the virtual machine, which is provided to the new host of the virtual machine. The cache data may be transferred via a network transfer.
Type:
Grant
Filed:
July 3, 2012
Date of Patent:
April 4, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Vikram Joshi, Yang Luan, Michael Brown, Bhavesh Mehta
Abstract: Techniques are disclosed for accurately sensing memory cells without having to wait for a voltage that creeps up on word line after a sensing operation to die down. The word line creep up could cause electrons to trap in shallow interface traps of a memory cell, hence impacting its threshold voltage. In one aspect, trapped electrons are removed (e.g., de-trapped) from shallow interface traps of a memory cell using a weak erase operation. Therefore, problems associated with word line voltage creep up are reduced or prevented. Thus, the memory cell can be sensed without waiting, while still providing an accurate result. The weak erase could be part of a sensing operation, but that is not required. For example, the weak erase could be incorporated into the beginning part of a read operation, which provides for a very efficient solution.
Abstract: A non-volatile data storage device comprises pairs of immediately adjacent and isolated-from-one-another local bit lines that are independently driven by respective and vertically oriented bit line selector devices. The isolation between the immediately adjacent and isolated-from-one-another local bit lines also isolates from one another respective memory cells of the non-volatile data storage device such that leakage currents cannot flow from memory cells connected to a first of the immediately adjacent and isolated-from-one-another local bit lines to memory cells connected to the second of the pair of immediately adjacent and isolated-from-one-another local bit lines. A method programming a desire one of the memory cells includes applying boosting voltages to word lines adjacent to the bit line of the desired memory cell while not applying boosting voltages to word lines adjacent to the other bit line of the pair.
Abstract: Apparatus and methods implemented therein use an ECC procedure to verify and correct errors in data corresponding to pre-programmed configuration data. Verification and correction is performed in a memory system comprising a non-volatile memory (NVM) and a read only memory (ROM). The NVM comprises a plurality of memory pages. On detecting a power-on reset (POR) command at the memory system, a determination is made whether the memory system has previously received the POR command from a host. When it is determined that the memory system has not previously received the POR command from the host, pre-programmed configuration data is read from the ROM and the memory system is initialized using the pre-programmed configuration data. An error correction code (ECC) is generated for the pre-programmed configuration data and the pre-programmed configuration data including the ECC is store in one of the plurality of pages of the NVM memory.
Type:
Grant
Filed:
May 6, 2015
Date of Patent:
March 28, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Nian Yang, Abhijeet Manohar, Daniel Edward Tuers
Abstract: A semiconductor device comprises a set of selection transistors, such as in a three-dimensional memory structure or stack having resistance change memory cells arranged along vertical bit lines. Each selection transistor has a non-shared control gate and a shared control gate. The transistor bodies may have an unequal pitch and a common height. Some of the transistor bodies can be misaligned with the vertical bit lines to fit the transistors to the stack. A method for programming the three-dimensional memory structure includes forming one or two channels in a transistor body to provide a current to selected memory cells. Programming can initially use one channel and subsequently use two channels based on a programming progress. A method for fabricating a semiconductor device includes etching a gate conductor material so that shared and non-shared control gates have a common height.
Abstract: A method is provided that includes forming a first vertical bit line disposed in a first direction above a substrate, forming a first word line disposed in a second direction above the substrate, the second direction perpendicular to the first direction, forming a first memory cell comprising a nonvolatile memory material at an intersection of the first vertical bit line and the first word line, forming a transistor above the substrate, and forming a first bit line select device coupled between the first vertical bit line and the transistor.
Abstract: A 3D nonvolatile memory has memory elements arranged in a three-dimensional pattern with a plurality of memory layers stacked over a semiconductor substrate. It has a 2D array of vertical bit lines and a plurality of staircase word lines. Each staircase word line has a series of alternating segments and risers and traverses the plurality of memory layers with a segment in each memory layer. The plurality of staircase word lines have their segments lined up to form a 2D array of stacks of segments. Riser for a pair of segments from each adjacent stacks at different memory layers is provided by a conductive sidewall layer of a stairwell disposed between the adjacent stacks. Multiple insulated conductive sidewall layers provide multiple risers for the adjacent stacks. Layer-by-layer stairwell excavation and sidewall processes between adjacent stacks create risers for different pairs of segments between stacks to form the staircase word lines.
Abstract: Techniques are provided for efficiently performing programming operations in a memory device. In particular, power consumption is reduced in sensing circuitry by avoiding pre-charging of bit lines for certain memory cells at certain times during a programming operation. One approach uses knowledge of the different phases of a programming operation to reduce the number of unnecessary bit line pre-charges. For example, during the lower program loop numbers of a programming operation, bit line pre-charging may occur for lower data states but not for higher data states. Similarly, during the higher program loop numbers, bit line pre-charging may occur for higher data states but not for lower data states. In another approach, which may or may not incorporate knowledge of the different phases of a programming operation, the setting of the bit line pre-charge can be updated at least once after it is initially set in the verify portion.
Type:
Grant
Filed:
August 7, 2014
Date of Patent:
March 14, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Man L Mui, Yee Lih Koh, Yenlung Li, Cynthia Hsu
Abstract: In NAND Flash memory, bit line precharge/discharge times can be a main component in determining program, erase and read performance. In a conventional arrangement bit line levels are set by the sense amps and bit lines are discharged to a source line level is through the sense amplifier path. Under this arrangement, precharge/discharge times are dominated by the far-side (relative to the sense amps) based on the bit lines' RC constant. Reduction of bit line precharge/discharge times, therefore, improves NAND Flash performance and subsequently the overall system performance. To addresses this, an additional path is introduced between bit lines to the common source level through the use of dummy NAND strings. In an exemplary 3D-NAND (BiCS) based embodiment, the dummy NAND strings are taken from dummy blocks, where the dummy blocks can be placed throughout the array to evenly distribute the discharging current.
Type:
Grant
Filed:
September 24, 2014
Date of Patent:
March 14, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Juan Carlos Lee, Hao Nguyen, Man Mui, Tien-chien Kuo, Yuki Mizutani
Abstract: A method is provided for programming a non-volatile memory. The method includes programming memory cells for even bit lines by programming the memory cells into a plurality of intermediate data states from an erased state, and for each of the intermediate data states, concurrently programming the memory cells to a plurality of target data states. The method also includes programming memory cells for odd bit lines by programming the memory cells into the plurality of intermediate data states from an erased state, and for each of the intermediate data states, concurrently programming the memory cells to the plurality of target data states.
Type:
Grant
Filed:
October 30, 2015
Date of Patent:
March 14, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Yen-Lung Li, Raul-Adrian Cernea, Jong Hak Yuh, Tai-Yuan Tseng
Abstract: A method is provided for reading a memory cell of a nonvolatile memory system. The method includes generating a hard bit and N soft bits for the memory cell in a total time corresponding to a single read latency period and N+1 data transfer times.
Type:
Grant
Filed:
March 31, 2016
Date of Patent:
March 14, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Chang Siau, Jeffrey Koon Yee Lee, Tianhong Yan, Yingchang Chen, Gopinath Balakrishnan, Tz-yi Liu
Abstract: A method is provided for operating a reversible resistance-switching memory cell. The method includes programming the reversible resistance-switching memory cell to three or more memory states while limiting the current through the memory cell to less than between about 0.1 microamp and about 30 microamps.
Abstract: Techniques are provided for periodically monitoring and adjusting the threshold voltage levels of memory cells in a charge-trapping memory device. When a criterion is met, such as based on the passage of a specified time period, the memory cells are read to classify them into different subsets according to an amount of downshift in threshold voltage (Vth). Two or more subsets can be used per data state. A subset can also comprise cells which are corrected using Error Correction Code (ECC) decoding. The subsets of memory cells are refresh programmed, without being erased, in which a Vth upshift is provided in proportion to the Vth downshift. The refresh programming can use a fixed or adaptive number of program pulses per subset. Some cells will have no detectable Vth downshift or a minor amount of Vth downshift which can be ignored. These cells need not be refresh programmed.
Abstract: A system and method are disclosed for incorporating mathematical and/or logical functionality within a memory system (such as a solid state drive (SSD)). The mathematical and/or logical functionality may comprise an arithmetic logic unit (ALU). The ALU may be resident in one or both of flash memory chips or the SSD controller. When resident in the flash memory chips, a single ALU or multiple ALUs may be used. For example, a single ALU may be assigned to one, some, or each block of flash memory within the flash memory chip. As another example, an ALU may be assigned to a sub-block construct, such as to each bit line in the block. Having ALUs resident in the SSD enables more processing to be performed within the SSD and reduces the need to transmit data outside of the SSD for processing.
Abstract: A method is provided for operating a non-volatile storage system that includes a plurality of bit lines, a word line comb including a plurality of word lines, and a plurality of memory elements, each memory element coupled between one of the bit lines and one of the word lines. The method includes receiving a current conducted by the word line comb, estimating a resistance of a conductive path between the word line comb and a selected word line voltage node, and generating a voltage at the selected word line voltage node based on the received current and the estimated resistance so that a voltage of the word line comb substantially equals a reference voltage.
Type:
Grant
Filed:
February 4, 2016
Date of Patent:
March 14, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Yingchang Chen, Jeffrey Koonyee Lee, Chang Siau, Anurag Nigam, Thomas Yan
Abstract: A monitoring application and method for using a monitoring application are disclosed. The monitoring application is configured to manage file system objects in a memory device layer (including copying of the file system objects) and is configured to manage one or more data structures to enable the management of the file system objects to be transparent to the application layer and/or the operating system layer.
Abstract: Systems, apparatuses, and methods may be provided that adapt to trim set advancement. Trim set advancement may be a change in trim sets over time. A cell of a semiconductor memory may have a first charge level and be programmed with a first trim set. The cell may be reprogrammed by raising the first charge level to a second charge level that corresponds to the cell programmed with a second trim set.
Type:
Grant
Filed:
October 6, 2014
Date of Patent:
March 7, 2017
Assignee:
SanDisk Technologies LLC
Inventors:
Gautam Dusija, Chris Avila, Jonathan Hsu, Neil Darragh, Bo Lei