Micron Technology Incorporated

AbdelHakim S Alhussien

Sivagnanam Parthasarathy

Patrick Robert Khayat

James Fitzpatrick

Violante Moschiano

A memory device to determine a voltage optimized to read a group of memory cells. In response to a command, the memory device reads the group of memory cells at a plurality of test voltages to determine a set of signal and noise characteristics of the group of memory cells. The memory device determines or recognizes a shape of a distribution of the signal and noise characteristics over the plurality of test voltages. Based on the shape, the memory device selects an operation in determining an optimized read voltage of the group of memory cells.

Determine optimized read voltage via identification of distribution shape of signal and noise characteristics

A memory sub-system to track charge loss in memory cells and shifts of voltages optimized to read the memory cells. For example, a memory device can measure signal and noise characteristics of a group of memory cells to calculate an optimized read voltage of the group of memory cells. The memory sub-system having the memory device can determine an amount of charge loss in the group of memory cells, using at least the signal and noise characteristics, the optimized read voltage, and/or the bit error rate of data read using the optimized read voltage. The memory sub-system tracks changes in optimized read voltages of memory cells in the memory device based on the amount of charge loss.

Track charge loss based on signal and noise characteristics of memory cells collected in calibration operations

A memory sub-system configured to execute a read command of a first type using a combine process to read soft bit data and hard bit data from memory cells. For example, a memory device is to: measure signal and noise characteristics of memory cells for the read command; calculate, based on the characteristics, an optimized voltage and two adjacent voltages that have offsets of a same amount from the optimized voltage; read the memory cells for hard bit data using the optimized voltage and for soft bit data using the two adjacent voltages; and transmit, to the processing device, a response including the hard bit data. The soft bit data can be selectively transmitted based on a classification determined from the characteristics. When a read command of a second type is executed, soft bit data is not read; and/or the signal and noise characteristics are not measured.

Reading of soft bits and hard bits from memory cells

A memory sub-system configured to: measure a plurality of sets of signal and noise characteristics of a group of memory cells in a memory device; determine a plurality of optimized read voltages of the group of memory cells from the plurality of sets of signal and noise characteristics respectively; generate features from the plurality of sets of signal and noise characteristics, including at least one compound feature generated from the plurality of sets of signal and noise characteristics; generate, using the features, a classification of a bit error rate of data retrievable from the group of memory cells; and control an operation to read the group of memory cells based on the classification.

Classification of error rate of data retrieved from memory cells

A memory device to program a group of memory cells to store multiple bits per memory cell. Each bit per memory cell in the group from a page. After determining a plurality of read voltages of the group of memory cells, the memory device can read the multiple pages of the group using the plurality of read voltages. For each respective page in the multiple pages, the memory device can determine a count of first memory cells in the respective page that have threshold voltages higher than a highest read voltage, among the plurality of read voltages, used to read the respective page. The count of the first memory cells can be compared with a predetermined range of a fraction of memory cells in the respective page to evaluate the plurality of read voltages (e.g., whether any of the read voltages is in a wrong voltage range).

Detection of an incorrectly located read voltage

A memory device to perform a read disturb mitigation operation. For example, the memory device can measure signal and noise characteristics of a group of memory cells to determine an optimized read voltage of the group of memory cells and determine a margin of read disturb accumulated in the group of memory cells. Subsequently, the memory device can identify the group of memory cells for the read disturb mitigation operation based on the margin of read disturb and a predetermined threshold.

Read disturb mitigation based on signal and noise characteristics of memory cells collected for read calibration

A memory device to determine a voltage window to read soft bit data. For example, in response to a read command, the memory device can read a group of memory cells at a plurality of test voltages to determine signal and noise characteristics, which can be used to determine an optimized read voltage for reading hard bit data and a voltage window between a first voltage and a second voltage for reading soft bit data. The soft bit data identifies exclusive or (XOR) of results read from the group of memory cells at the first voltage and at the second voltage respective. The memory device can provide a response to the read command based on the hard bit data and the soft bit data.

Optimization of soft bit windows based on signal and noise characteristics of memory cells

A memory sub-system configured to adaptively and/or iteratively determine sub-operations of executing a read command to retrieve data from memory cells. For example, after receiving the read command from a processing device of a memory sub-system, a memory device starts an atomic operation of executing the read command in the memory device. The memory device can have one or more groups of memory cells formed on an integrated circuit die and a calibration circuit configured to measure signal and noise characteristics of memory cells in the memory device. During the atomic operation, the calibration circuit generates outputs, based on which a read manager of the memory sub-system identifies sub-operations to be performed in the atomic operation and/or decides to end the atomic operation.

Adaptive and/or iterative operations in executing a read command to retrieve data from memory cells

A memory sub-system configured to iterative calibrate read voltages, where higher read voltages are calibrated based on the calibration results of lower read voltages. For example, a memory device initially determines first read voltages of a group of memory cells. The memory device calculates a second read voltage optimized to read the group of memory cells according to first signal and noise characteristics measured based on at least one of the first read voltages. A third read voltage is estimated based on an offset of the second read voltage from a corresponding voltage among the first read voltages. Second signal and noise characteristics of the group of memory cells are measured based on the third read voltage. The memory device then calculates a fourth read voltage optimized to read the group of memory cells according to the second signal and noise characteristics.

Self adapting iterative read calibration to retrieve data from memory cells

A memory sub-system configured to dynamically select an option to process encoded data retrieved from memory cells of a memory component, based on a prediction generated using signal and noise characteristics of memory cells storing the encoded data. For example, the memory component is enclosed in an integrated circuit and has a calibration circuit. The signal and noise characteristics are measured by the calibration circuit as a byproduct of executing a read command in the memory component to retrieve the encoded data. A data integrity classifier configured in the memory sub-system generates a prediction based on the signal and noise characteristics. Based on the prediction, the memory sub-system selects an option from a plurality of options configured in the memory sub-system to process the encoded data.

Dynamic adjustment of data integrity operations of a memory system based on error rate classification

Compound feature generation in classification of error rate of data retrieved from memory cells

A memory sub-system configured to improve performance using signal and noise characteristics of memory cells measured during the execution of a command in a memory component. For example, the memory component is enclosed in an integrated circuit and has a calibration circuit. The signal and noise characteristics are measured by the calibration circuit as a byproduct of executing the command in the memory component. A processing device separate from the memory component transmits the command to the memory component, and receives and processes the signal and noise characteristics to identify an attribute about the memory component. Subsequently, an operation related to data stored in the memory component can be performed based on the attribute.

Memory system performance enhancements using measured signal and noise characteristics of memory cells

A memory device to generate intelligent, proactive responses to a read command. For example, signal and noise characteristics of a group of memory cells in a memory device are measured to determine a read voltage. An action is identified based on evaluation of the quality of data retrievable using the read voltage from the group of memory cells. While a response indicating the action is provided responsive to the command, the memory device can initiate the action proactively before a subsequent command, following the response, is received.

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San Jose, CA, United States of America

AbdelHakim S Alhussien