Nonvolatile semiconductor memory and method for driving the same

Abstract

To provide a NOR-type nonvolatile semiconductor memory that can inject electric charge into a charge accumulation layer through the use of an FN tunnel current without compromising an increase in the packing density of memory cells. The above problem is solved by a nonvolatile semiconductor memory in which nonvolatile semiconductor memory cells are arranged in a matrix, each nonvolatile semiconductor memory cell having an island semiconductor layer in which a drain diffusion layer formed in the upper part of the island semiconductor layer, a source diffusion layer formed in the lower part of the island semiconductor layer, a charge accumulation layer formed on a channel region of the side wall sandwiched between the drain diffusion layer and the source diffusion layer via a gate insulation film, and a control gate formed on the charge accumulation layer are formed. Further, bit lines connected to the drain diffusion layer are laid out in a column direction, control gate lines are laid out in a row direction, and source lines connected to the source diffusion layer are laid out in the column direction.