Semiconductor storage device

摘要

Device isolation/insulation films each have a first height within a first area and a second height higher than the first height within a second area. At least the device isolation/insulation films adjacent to a contact diffusion region exist in the second area, and the device isolation/insulation films adjacent to memory transistors exist in the first area. The device isolation/insulation films are implanted with an impurity of a first conductivity type, and device formation regions each have a diffusion region of the first conductivity type, the diffusion region being formed by diffusion of the impurity of the first conductivity type from the device isolation/insulation films.