SEMICONDUCTOR MEMORY DEVICE AND ITS MANUFACTURE

PURPOSE: To increase cell capacitance by extending the effective area of the capacitor of a memory device. CONSTITUTION: In a semiconductor memory device plurally provided with memory cells consisting of one transistor and one capacitor on a semiconductor substrate, a part of the capacitor is connected with the source areas 7 of the transistors and a storage electrode provided with box-shaped tunnels 21 communicated with outside is provided at their center parts. Thereby, the semiconductor memory device increases the effective areas of the capacitors compared with a conventional semiconductor memory device to improve a storing capacity and is provided with excellent characteristic in falattening.