SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE:To realize a large-scale memory by integrating a transistor and a capacitor to a solumnar projection formed to the surface of a semicondutor substrate and shaping the memory cell of one bit to one columnar projection. CONSTITUTION:A silicon substrate 301 is dry-etched to form columnar projections 300 consisting of silicon. A superposed film 309 composed of SiO2 and Si3 N4 is shaped on the surfaces of the projections 300 as an insulating film for a capacitor. SiO2 312 is formed as a gate insulating film for a peripheral circuit and a gate insulating film for a switching transistor, and poly Si 313 is applied on the SiO2 312 as gate electrodes. The capacitance of a capacitor and the conductance of the transistor required for memory operation are obtained though the area of a plane is small because the capacitor and the switching transistor for a memory cell are integrated to one columnar projection.