Intel Corporation

Micron Technology Incorporated

Prashant S Damle

Kiran Pangal

Doyle W Rivers

Krishna Kumar Parat

Rajesh Sundaram

Shekoufeh Qawami

Julie M Walker

Akira Goda

Zion S Kwok

Davide Mantegazza

Frank T Hady

Paul D Ruby

Richard Paul Mangold

Alessandro Torsi

Shafqat Ahmed

Hanmant Pramod Belgal

Carlo Musilli

Sowmiya Jayachandran

Kunal A Khochare

Philip Hillier

Wei Fang

Kalpana Vakati

Tomoharu Tanaka

Derchang Kau

Robert W Faber

Raymond W Zeng

Muthukumar Swaminathan

Davide Fugazza

Ningde Xie

Jeffrey W Ryden

Abhinav Pandey

Gerard H Joyce

Feng Q Pan

Nevil N Gajera

Ravi H Motwani

Mase J Taub

Albert Fazio

Nathan Franklin

Daniel Chu

Sanjay Rangan

Benjamin Graniello

Hemant P Rao

Dany-Sebastien Ly-Gagnon

Sebastian T Uribe

Nathan R Franklin

Arjun Kripanidhi

Ashir G Shah

Rakan Maddah

Akanksha Mehta

Hu Chaohong

Daniel J Chu

Hanmant P Belgal

A read technique for both SLC (single level cell) and MLC (multi-level cell) cross-point memory can mitigate drift-related errors with minimal or no drift tracking. In one example, a read at a higher magnitude voltage is applied first, which causes the drift for cells in a lower threshold voltage state to be reset. In one example, the read at the first voltage can be a full float read to minimize disturb. A second read can then be performed at a lower voltage without the need to adjust the read voltage due to drift.

Cross-point memory read technique to mitigate drift errors

A write history buffer can prevent write disturb in memory, enabling a reduction in write disturb refresh rate and improvement in performance. A memory device can include circuitry to cause consecutive write commands to the same address to be spaced by an amount of time to reduce incidences of write disturb, and therefore reduce the required write disturb refresh rate and improve performance. In one example, a memory device receives multiple write commands to an address. In response to receipt of the multiple write commands, the first write command is sent to the memory and a timer is started. Subsequent write commands that are received after the first write command and before expiration of the timer are held in a buffer. After expiration of the timer, only the most recent of the subsequent write commands to the address is sent to the memory array. In this way, the subsequent write commands received during a time window after the first write command are coalesced and a single subsequent write command is sent to the memory.

Write disturb refresh rate reduction using write history buffer

Uncorrectable memory errors may be reduced by determining a logical array address for a set of memory arrays and transforming the logical array address to at least two unique array addresses based, at least in part, on logical locations of at least two memory arrays within the set of memory arrays. The at least two memory arrays are then accessed using the at least two unique array addresses, respectively.

Reduced uncorrectable memory errors

In one embodiment, an apparatus comprises a first memory array comprising a plurality of phase change memory (PCM) cells; and a controller to track a first cycle count metric based at least in part on a number of writes performed to at least a portion of the first memory array; and adjust, based on the first cycle count metric, a demarcation voltage to be applied during read operations performed on PCM cells of the first memory array.

Method and apparatus for adjusting demarcation voltages based on cycle count metrics

A memory device includes a memory array having multiple nonvolatile memory cells that stores data as a set or a reset state of the memory cells. The nonvolatile memory cells can be resistance-based memory, which stores data based on resistive state of the memory cells. A controller coupled to the memory array periodically samples set and reset margins for memory cells of the memory array. Responsive to detection of a change in a margin, the system can adaptively adjust a preset electrical setting used to differentiate between a set state and a reset state.

Memory preset adjustment based on adaptive calibration

In one embodiment, an apparatus comprises a memory array comprising a plurality of phase change memory (PCM) cells; and a controller to determine to read data stored by the plurality of PCM cells independent of a read command from a host device; and in response to the determination to read data stored by the plurality of PCM cells independent of a read command from a host device, perform a dummy read operation on the plurality of PCM cells and perform an additional read operation on the plurality of PCM cells.

Method and apparatus for reducing silent data errors in non-volatile memory systems

One embodiment provides a memory controller. The memory controller includes a memory controller memory; a timestamp circuitry and a demarcation voltage (VDM) selection circuitry. The timestamp circuitry is to capture a current timer index from a timer circuitry in response to an initiation of a periodic patrol scrub and to compare the current timer index to a stored timestamp. The VDM selection circuitry is to update a state of a sub-block of a memory array, if the state is less than a threshold and a difference between the current timer index and the stored timestamp is nonzero. The timestamp circuitry is further to store the current timer index as a new timestamp.

Time tracking with patrol scrub

In an embodiment, a memory controller may determine that one or more neighboring memory cells associated with a target memory cell in a memory device are to be refreshed. The controller may generate a command associated with refreshing the one or more neighboring memory cells. The controller may transfer the command from the memory controller to the memory device containing the target memory cell. The command may direct the memory device to refresh the neighboring memory cells and/or return one or more addresses associated with the neighboring memory cells.

Managing disturbance induced errors

Apparatus, systems, and methods to correct for threshold voltage drift in non-volatile memory devices are disclosed and described. In one example, a compensated demarcation voltage is generated by either a time-based drift compensation scheme or a disturb-based drift compensation scheme, and read and write operations to the non-volatile memory are carried out using the compensated voltage threshold.

Managing threshold voltage shift in nonvolatile memory

In response to a write operation on a storage element in a non-volatile memory device, a count provided by a global counter is stored to indicate a time at which the write operation occurs on the storage element. In response to receiving a request perform a read operation on the storage element, a determination is made of a demarcation voltage to apply for performing the read operation on the storage element, based on a progress of the global counter since the write operation on the storage element.

Determining demarcation voltage via timestamps

A disclosed example to reduce a threshold voltage drift of a selector device of a memory cell includes providing an applied voltage to the selector device of the memory cell, the applied voltage being less than a threshold voltage of the selector device, and reducing the threshold voltage drift of the memory cell by maintaining the applied voltage at the selector device for a thresholding duration to activate the selector device.

Methods and apparatus to reduce threshold voltage drift

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Portland, OR, United States of America

Prashant S Damle