Patent ID: 7961524

Claim:
A method for driving a nonvolatile semiconductor memory device comprising source/drain diffusion layers spaced from each other in a surface portion of a semiconductor substrate, a laminated insulating film formed on a channel between the source/drain diffusion layers and including a charge storage layer, and a gate electrode formed on the laminated insulating film, the nonvolatile semiconductor memory device having a first data memory state and a second data memory state different from the first data memory state, the method comprising: performing a first operation to change to the first data memory state from the second data memory state; and performing a second operation to change to the second data memory state from the first data memory state, the performing the first operation including: injecting first charges having a first polarity into the charge storage layer from the semiconductor substrate; and after injecting the first charges into the charge storage layer, injecting second charges having a second polarity opposite to the first polarity into the charge storage layer from the semiconductor substrate by providing a potential difference between the semiconductor substrate and the gate electrode, the performing the second operation including injecting third charges having the second polarity into the charge storage layer from the semiconductor substrate.