Structures, methods, and systems for enhanced erasing operation for non-volatile memory are disclosed. In one embodiment, a semiconductor device which comprises a memory cell array having a plurality of non-volatile memory cells, a negative voltage generating circuit for applying a negative voltage to a word line of the memory cell array during an erasing operation of the memory cell array, and a positive voltage generating circuit for applying a positive voltage to a well of the memory cell array when the negative voltage reaches a predetermined voltage.