SEMICONDUCTOR STORAGE AND ITS MANUFACTURING METHOD

摘要

A memory cell of an SRAM is composed of a transfer MISFET, a drive MISFET, and a load MISFET fabricated over the drive MISFET. The load MISFET has a vertical structure where a gate electrode (23) is disposed over the side face of a multilayer structure (P) extending perpendicularly to a major surface of a semiconductor substrate (1), with a gate insulating film (22) interposed between the gate electrode (23) and the multilayer structure (P). The multilayer structure (P) is composed of polycrystalline silicon films: a lower semiconductor layer (13), an intermediate semiconductor layer (14), and an upper semiconductor layer (15) in order from below.