Semiconductor memory devices that are configured to analyze read failures and related methods of operating such devices

摘要

Semiconductor memory devices are provided that include a nonvolatile memory that has a plurality of memory cells and a memory controller that is configured to control at least some of the operations of the nonvolatile memory. The memory controller include an error correction unit. Moreover, the memory controller is configured to determine whether a read failure that occurs during a read operation of a first of the plurality of memory cells is due to charge leakage based at least in part on an output of the error correction unit. Related methods are also disclosed.

主权项

1. A semiconductor memory device comprising:
a nonvolatile memory that includes a plurality of memory cells; an error correction unit; and a controller that is configured to:
determine, using an output of the error correction unit, that a read failure occurred during a read operation of a first of the plurality of memory cells;determine, by changing a selective read voltage, whether the read failure resulted because the first of the plurality of memory cells was programmed with data having a first value but was sensed as storing data having a second value or because the first of the plurality of memory cells was programmed with data having the second value but was sensed as storing data having the first value; andrepair the read failure if it is due to charge leakage or to soft-programming by re-programming, and to repair the read failure if it is due to over-programming by increasing a non-selective read voltage.