Nonvolatile semiconductor memory device

摘要

A nonvolatile semiconductor memory device includes a memory cell array having nonvolatile memory cells in which one of multiple values is programmable therein by setting one of a plurality of threshold values therein and a control circuit that performs a writing operation on the memory cells. The writing operation performed by the control circuit includes a pre-programming verification operation to determine a threshold level of a memory cell in an erasure state, and a program operation in which a program voltage is selected from a plurality of program voltages on the basis of a determination result of the pre-programming verification operation.

主权项

1. A nonvolatile semiconductor memory device comprising:
a memory cell array having nonvolatile memory cells in which one of multiple values is programmable therein by setting one of a plurality of threshold values therein; and a control circuit configured to perform a writing operation on the memory cells of the memory cell array, wherein the writing operation performed on a memory cell in an erasure state includes a pre-programming verification operation to determine a threshold level of the memory cell in the erasure state and a program operation in which a program voltage for the memory cell is selected from a plurality of program voltages based on a determination result of the pre-programming verification operation, wherein the control circuit selects and writes a first program voltage to a memory cell which is determined to have a threshold level larger than a reference value in the pre-programming verification operation, and selects and writes a second program voltage lower than the first program voltage to a memory cell which is determined to have a threshold level smaller than the reference value in the pre-programming verification operation.