Write scheme for charge trapping memory

摘要

In a charge trapping memory, data that would otherwise be likely to remain adjacent to unwritten word lines is written three times, along three immediately adjacent word lines. The middle copy is protected from charge migration on either side and is considered a safe copy for later reading. Dummy data may be programmed along a number of word lines to format a block for good data retention.

主权项

1. A method of operating an array of charge-trapping memory cells comprising:
receiving a portion of data to be stored in the array; determining whether the portion of data is likely to be affected by charge migration between charge-trapping memory cells; and if the portion of data is likely to be affected by charge migration then storing a first copy of the portion of data along a first word line, storing a second copy of the portion of data along a second word line, and storing a third copy of the portion of data along a third word line, the first and third word lines lying immediately adjacent to the second word line on either side, the first, second, and third copies of the portion of data aligned so that each bit in a memory cell along the second word line is identical to bits in neighboring cells along the first and third word lines.