Nonvolatile semiconductor memory

Abstract

A nonvolatile semiconductor memory includes: a memory cell array constituted by word lines, bit lines, and electrically erasable/rewritable memory cell transistors, which have respective tunnel insulating films and are arranged at the intersections of the word lines and the bit lines; and a word line transfer transistor, which is separated by an element isolation region, has a source diffusion layer, a channel region, a gate insulating film on the channel region, and a drain diffusion layer, and is connected to a word line and a gate electrode formed on the gate insulating film via a word line contact plug formed in the drain diffusion layer. The channel width of the word line transfer transistor is at least six times width of the word line contact plug, and the distance in a second direction between the word line contact plug and corresponding element isolation region is greater than distance in a first direction between the word line contact plug and corresponding element isolation region where, the first direction denotes a direction from the source diffusion layer towards the drain diffusion layer, and the second direction denotes a direction perpendicular to the first direction.