SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To provide a highly reliable DRAM by obtaining a desired threshold voltage in a memory cell and at the same time improving refresh characteristics. SOLUTION: A threshold voltage of 1.1 V of a memory cell selecting MISFET (Qs) is obtained by forming a p-type semiconductor region 27 and n--type semiconductor regions 8a, 8b whose impurity concentration is relatively high in a p-type well 4 on a data line side of the memory cell selecting MISFET (Qs). Junction field strength near the end part at an information storing capacity element side of a gate electrode 7a is reduced, by not forming the p-type semiconductor region 27 in the p-type well 4 at an information storing capacity element side but by forming the n--type semiconductor region 8b whose impurity concentration is relatively low.