THREE-LEVEL NONVOLATILE SEMICONDUCTOR MEMORY DEVICE WHICH REDUCES COUPLING NOISE BETWEEN MEMORY CELLS, AND ITS DRIVING METHOD

摘要

PPROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device having a high degree of integration and high reliability, and to provide its driving method. PSOLUTION: A three-level nonvolatile semiconductor memory device which reduces coupling noise between memory cells and its driving method are disclosed. The nonvolatile semiconductor memory device of the present invention includes memory cells that can be controlled to three threshold voltage levels and a page buffer for controlling the memory cells, and has a higher degree of integration than does a two-level nonvolatile semiconductor memory device and higher reliability than does a four-level nonvolatile semiconductor memory device. In the nonvolatile semiconductor memory device, memory cells which are controlled to have a relatively small voltage difference in the second and third page program steps are arranged at the left and right sides of the first memory cell, which is programmed to the second threshold voltage group in the first page program step. Accordingly, the nonvolatile semiconductor memory device and the driving method of the present invention can reduce coupling noise between memory cells in a worst case condition. PCOPYRIGHT: (C)2007,JPO&INPIT