Grown defect detection and mitigation using ecc in memory systems

A circuit comprising:

• a memory configured to store a data set received from a memory die during a read operation;
• a check circuit configured to calculate a plurality of numbers of unsatisfied checks for a plurality of bit groups of the data set;
• an unreliable memory detection circuit configured to detect an unreliable memory cell based on the plurality of numbers of unsatisfied checks;
• and
• an initial reliability metric circuit configured to set an initial reliability metric value for a bit stored in the unreliable memory cell based on the detection.

A system comprising:

• a memory die;
• a controller comprising:
• a parity bit generator circuit configured to:
• generate a plurality of parity bits for a set of information bits based on an error correction code;
• and
• append the plurality of parity bits to the set of information bits to form a codeword;
• a memory interface circuit configured to output the codeword to the memory die for storage;
• a data retrieval circuit configured to receive the codeword from the memory die during a read operation;
• a scoring circuit configured to calculate a score for the codeword based on the error correction code used to generate the parity bits;
• and
• an unreliable memory identification circuit configured to detect that a portion of the codeword is stored in an unreliable group of memory cells based on the score.

A method comprising:

• receiving, with a controller, a data set during a read operation;
• calculating, with the controller, a plurality of empirical distributions for a plurality of groups of bits of the data set based on numbers of unsatisfied checks of the bits of the data set;
• detecting, with the controller, an unreliable bit line based on the plurality of empirical distributions;
• and
• storing, with the controller, an identifier that identifies the unreliable bit line in a memory.

A circuit comprising:

• a means for receiving a bit group of data stored in a memory array;
• a means for comparing an empirical distribution for the bit group with an expected distribution;
• and
• a means for identifying that the bit group is unreliable in response to the comparison.