SEMICONDUCTOR MEMORY DEVICE AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To improve the degree of integration and read speed of a mask ROM which stores information by changing the thresholds of transistors by improving the microminiaturization limit of the transistors by short channel effects. SOLUTION: A semiconductor memory device is provided with a first diffusion area 22a which constitutes a bit line and, at the same time, part of which also works as the source area of a memory transistor and a second diffusion area 22b which contains the drain area of the memory transistor and the diffusion areas 22a and 22b are constituted to have projecting sections protruded from a plane containing the surface of the channel area of the memory transistor.