Nonvolatile semiconductor memory device and method for controlling nonvolatile semiconductor memory device

Abstract

A semiconductor memory device of embodiments includes a semiconductor layer, a gate electrode layer, memory cells each including a gate insulating layer containing Si, O, and N, and a control circuit. The control circuit performs a write operation and an erase operation on the memory cells. The control circuit determine whether or not the number of times of execution of the erase operation on the memory cells has reached a predetermined number of times. When the number has reached the predetermined number of times, the control circuit perform first processing and second processing on the memory cells. The first processing applies a voltage with the same polarity as that in the write operation to the gate electrode layer with a pulse width larger than that in the write operation. The second processing applies a voltage with a polarity opposite to that in the write operation to the gate electrode layer.