Nonvolatile semiconductor memory device with memory cells, each having an fg cell transistor and select gate transistor, and a method of writing data into the same

Abstract

A semiconductor device comprises a memory cell array and a source line driver. Each of the memory cells in the memory cell array has a floating gate cell transistor which stores data by accumulating charge in the floating gate and a select gate transistor whose drain is connected to the source of the cell transistor and whose source is connected to a source line. The source line driver is configured so as to drive the source line in a write operation at a potential between the substrate bias potential of the cell transistor and select gate transistor and the ground potential.