Nonvolatile semiconductor memory device

Abstract

Nonvolatile semiconductor memory device according to one embodiment includes: a plurality of planes; a memory cell array provided in the plurality of planes respectively; bit lines; and a control circuit. Each memory cell array is configured as an array of NAND cell units each including a memory string. The memory string includes a plurality of nonvolatile memory cells connected in series. The bit lines are connected to a first end of the NAND cell units, respectively. The control circuit controls a write operation of charging the bit lines up to a certain voltage value, and then setting data in the nonvolatile memory cells to a certain threshold voltage distribution state. The control circuit is configured to be capable of executing an operation of charging the bit lines in a write operation by varying timings of starting charging the bit lines among the plurality of planes.