# US 2022/0044756 A1 · Read Model of Memory Cells using Information Generated during Read Operations

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- Number: US 2022/0044756 A1
- Document ID: US20220044756A1
- Status: Published application
- Kind: A1
- Application number: 17/401,213
- Filed: 2021-08-12
- Published: 2022-02-10
- Earliest claimed: 2020-08-07
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: James Fitzpatrick; Sivagnanam Parthasarathy; Patrick Robert Khayat; AbdelHakim S. Alhussien
- Web page: https://patentgrep.com/patent/US20220044756A1

## CPC

- G11C 7/14: Dummy cell management; Sense reference voltage generators
- G11C 29/44: Indication or identification of errors, e.g. for repair
- G06F 11/1048: {using arrangements adapted for a specific error detection or correction feature}
- G11C 7/02: with means for avoiding parasitic signals
- G11C 7/04: with means for avoiding disturbances due to temperature effects
- G11C 7/222: {Clock generating, synchronizing or distributing circuits within memory device}
- G11C 11/5642: {Sensing or reading circuits; Data output circuits}
- G11C 16/26: Sensing or reading circuits; Data output circuits
- G11C 16/3427: {Circuits or methods to prevent or reduce disturbance of the state of a memory cell when neighbouring cells are read or written}
- G11C 29/021: {in voltage or current generators}
- G11C 29/028: {with adaption or trimming of parameters}
- G11C 29/42: using error correcting codes [ECC] or parity check
- G11C 29/50004: {of threshold voltage}
- G11C 29/52: Protection of memory contents; Detection of errors in memory contents
- G11C 2207/2254: Calibration
- G11C: STATIC STORES (semiconductor memory devices H10B)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A memory sub-system configured to generate or update a model for reading memory cells in a memory device. For example, in response to a processing device of a memory sub-system transmitting to a memory device read commands that are configured to instruct the memory device to retrieve data from a group of memory cells formed on an integrated circuit die in the memory device, the memory device may measure signal and noise characteristics of the group of memory cells during execution of the read commands. Based on the signal and noise characteristics the memory sub-system can generate or update, measured during the execution of the read commands a model of changes relevant to reading data from the group of memory cells. The changes can be a result of damage, charge loss, read disturb, cross-temperature effect, etc.

## Claims

### Claim 1

A device, comprising:
an integrated circuit die;
memory cells formed on the integrated circuit die; and
a logic circuit configured to, in response to commands to read data from the memory cells,
measure signal and noise characteristics of a memory cell group, among the memory cells, to calibrate read voltages of the memory cell group; and
generate, based at least in part on the signal and noise characteristics of the memory cell group, a model of changes of the group of memory cells.

### Claim 2 (depends on 1)

The device of claim 1, comprising:
a calibration circuit configured to apply test voltages to the memory cell group to measure the signal and noise characteristics of the memory cell group.

### Claim 3 (depends on 2)

The device of claim 2, wherein the logic circuit is configured to generate the model by updating a prior model.

### Claim 4 (depends on 2)

The device of claim 2, wherein the logic circuit is configured to generate the model based on a history of the changes reflected at least in part in the signal and noise characteristics of the memory cell group measured during execution of the commands configured to read data from the memory cell groups.

### Claim 5 (depends on 4)

The device of claim 4, wherein the logic circuit is configured to track the history in association with operating parameters of the device during the execution of the commands.

### Claim 6 (depends on 5)

The device of claim 5, wherein the history identifies optimized read voltages determined based on the signal and noise characteristics of the memory cell group measured during the execution of the commands.

### Claim 7 (depends on 5)

The device of claim 5, wherein the history identifies classifications of quality of data retrieved using read voltages calibrated based on the signal and noise characteristics of the memory cell group measured during the execution of the commands.

### Claim 8 (depends on 5)

The device of claim 5, wherein the logic circuit is further configured to estimate, based on the signal and noise characteristics of the memory cell group, bit error rate of data retrieved from the memory cell group during the execution of the commands to generate the history.

### Claim 9 (depends on 5)

The device of claim 5, wherein the model identifies a property of the memory cell group as a function of time, temperature, or temperature change, or any combination thereof.

### Claim 10 (depends on 5)

The device of claim 5, wherein the model identifies changes in the memory cell group due to charge loss, read disturb, or cross-temperature effect, or any combination thereof.

### Claim 11 (depends on 5)

The device of claim 5, wherein the model identifies changes in damage in the memory cell group reflected from broadening of threshold voltage distribution.

### Claim 12 (depends on 5)

The device of claim 5, wherein the logic circuit is further configured to manage, based on the model, data placement, data refreshing, memory failure, or selection of parameters for programming, writing, erasing, or reading data.

### Claim 13

A method, comprising:
receiving, in a device having memory cells formed on an integrated circuit die, commands to read data from the memory cells;
measuring signal and noise characteristics of a memory cell group, among the memory cells;
calibrating read voltages of the memory cell group based on the signal and noise characteristics of a memory cell group; and
generating, based at least in part on the signal and noise characteristics of the memory cell group, a model of changes of the group of memory cells.

### Claim 14 (depends on 13)

The method of claim 13, comprising:
applying test voltages to the memory cell group; and
counting memory cells in the memory cell group having a predetermined status in response to each of the test voltages to generate data representative of the signal and noise characteristics of the memory cell group.

### Claim 15 (depends on 14)

The method of claim 14, further comprising:
tracking a history of a property of the memory cell group, based on the signal and noise characteristics of the memory cell group measured during execution of the commands, as a function of time, temperature, temperature change, or any combination thereof.

### Claim 16 (depends on 15)

The method of claim 15, wherein the model identifies changes in the memory cell group due to charge loss, read disturb, or cross-temperature effect, or changes in damage in the memory cell group reflected from broadening of threshold voltage distribution, or any combination thereof.

### Claim 17 (depends on 15)

The method of claim 15, further comprising:
managing, based on the model, data placement, data refreshing, memory failure, or selection of parameters for programming, writing, erasing, or reading data.

### Claim 18

A non-transitory computer storage medium storing instructions which, when executed in a device, cause the device to perform a method, the method comprising:
receiving, in the device having memory cells formed on an integrated circuit die, commands to read data from the memory cells;
measuring signal and noise characteristics of a memory cell group, among the memory cells;
calibrating read voltages of the memory cell group based on the signal and noise characteristics of a memory cell group; and
generating, based at least in part on the signal and noise characteristics of the memory cell group, a model of changes of the group of memory cells.

### Claim 19 (depends on 18)

The non-transitory computer storage medium of claim 18, wherein the method further comprises:
tracking a history of a property of the memory cell group, based on the signal and noise characteristics of the memory cell group measured during execution of the commands, as a function of time, temperature, temperature change, or any combination thereof.

### Claim 20 (depends on 19)

The non-transitory computer storage medium of claim 19, wherein the method further comprises:
managing, based on the model, data placement, data refreshing, memory failure, or selection of parameters for programming, writing, erasing, or reading data.