Semiconductor memory device which stores multilevel data

摘要

According to one embodiment, a semiconductor memory device includes a memory cell, a flag memory cell for a flag, a dummy cell and a controller. The flag memory cell is selected at the same time as the memory cell. The dummy cell is selected at the same time as the memory cell and the flag memory cell. The controller controls write and read of the memory cell, the flag memory cell and the dummy cell. Data is written also in the dummy cell which neighbors the flag cell.

主权项

1. A semiconductor memory device comprising:
a memory cell; a flag memory cell configured to store a flag, the flag memory cell being configured to be selected at the same time as the memory cell; a dummy cell configured to be selected at the same time as the memory cell and the flag memory cell; and a controller configured to control write and read of the memory cell, the flag memory cell and the dummy cell, wherein the controller is configured to set, by a first write operation, a threshold voltage of the memory cell from a first threshold voltage to the first threshold voltage or a second threshold voltage (first threshold voltage