Nonvolatile semiconductor memory device and method for manufacturing the same

摘要

A nonvolatile semiconductor memory device having a memory cell portion and peripheral circuit portion is disclosed. The nonvolatile semiconductor memory device has peripheral transistors formed in the peripheral circuit portion of a silicon substrate and cell transistors formed in the memory cell portion of the silicon substrate. The gate length of the cell transistor is shorter than the gate length of the peripheral transistor. Further, the nonvolatile semiconductor memory device has a silicon nitride film selectively formed on the memory cell portion. The silicon nitride film covers the cell transistors.