A method of erasing memory cells in a flash memory device that recombines
holes trapped in the tunnel oxide (after an erase operation) with
electrons passing through the tunnel oxide is disclosed. The method uses
an erase operation that over-erases all memory cells undergoing the erase
operation. A cell healing operation is performed on the over-erased cells.
The healing operation causes electrons to pass through the tunnel oxide
and recombine with trapped holes. The recombination substantially reduces
the trapped holes within the tunnel oxide without reducing the speed of
the erase operation. Moreover, by reducing trapped holes, charge
retention, overall performance and endurance of the flash memory cells are
substantially increased.