1. A method for reducing read failure in a memory device comprising a memory array having a drain side and a source side and a plurality of word lines, each coupled to a row of memory cells, between the drain side and the source side, the method comprising: determining proximity of a word line of memory cells to be erased to the drain side of the memory array; and varying a depth of erasure of the word line of memory cells in response to the proximity to the drain side.