Patent ID: 6816413
Filing Date: 2004-11-09
Classification: G11C

Abstract:
A nonvolatile semiconductor memory comprising:a plurality of nonvolatile memory cells each having a gate, a drain and a source to hold data corresponding to a threshold voltage level; a plurality of word lines connected to gates of the nonvolatile memory cells, respectively; a plurality of bit lines connected to drains of the nonvolatile memory cells, respectively; a plurality of source lines connected to sources of the nonvolatile memory cells, respectively; a reference current generation circuit which generates a reference current, the reference current generation circuit including at least one reference cell and an amplification circuit which amplifies a current flowing through the reference cell, and a ratio of an amplification factor of current in a program verify mode to an amplification factor of current in a data read mode is larger than 1; and a sense amplifier which compares the reference current with a current flowing through selected ones of the nonvolatile memory cells and reads data held in the selected ones of the nonvolatile memory cells.