SEMICONDUCTOR STORAGE DEVICE AND ITS MANUFACTURE

摘要

PURPOSE:To obtain a semiconductor storage device having a well structure which prevents undershoot occurring by an input signal and deterioration of transistor characteristics. CONSTITUTION:A plurality of N well regions and P well regions are formed on the main surface of a semiconductor substrate. The periphery of the P well region is surrounded by the N well region kept at a positive potential. Said N well region forms a junction between a P-type semiconductor substrate and the P well region. Said junction prevents electrons from being injected toward the P well region which electrons are generated from the P-type semiconductor substrate by shoot.