SEMICONDUCTOR MEMORY DEVICE AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a NAND flash memory semiconductor memory device for improving operation characteristics and a method of manufacturing the same relating to the implantation of impurities into the sidewalls of an active region. SOLUTION: The semiconductor memory device includes: a first active region where a memory MOS transistor is disposed; a second active region where a peripheral MOS transistor is disposed; a first trench 43 which is formed in a semiconductor substrate 10 and exposes the first active region on the sidewall; a first element isolating region which is provided with an insulating film buried in the first trench 43 and electrically separates the first active regions adjacent to each other; a second trench 43 which is formed in the semiconductor substrate 10 and exposes the second active region on the sidewall; and a second element isolating region 35 which is provided with an insulating film 27 buried in the second trench 43 and electrically separates the second active regions adjacent to each other. An impurity concentration in the second active region is higher than that in the central part, and the impurity concentration in the first active region AA is equal to that in the central part. COPYRIGHT: (C)2009,JPO&INPIT