PURPOSE: To increase the capacity of a semiconductor storage device by forming an information charge storage capacitor by utilizing the surface of a stepwise groove.
CONSTITUTION: A first capacitor for storing information charge comprises an n+ type impurity diffused layer 2a4, an insulating film 35a and a polycrystalline silicon layer 41. An MOS transistor Ta controls the read of the information charge from the first capacitor and the write of the information charge in the first capacitor. A second capacitor for storing information charge comprises an n+ type impurity diffused layer 2b4, an insulating film 35b and a polycrystalline silicon layer 41. An MOS transistor Tb controls the read of the information charge from the second capacitor and the write of the information charge in the second capacitor. Thus, stepwise grooves are formed of grooves 60, 62, and a grooved type information charge storage capacitor is formed by the surfaces of the grooves 60, 62 thereby to be able to store sufficient information charge even in a memory cell of small plane area.
ARIMOTO KAZUTAMI
FURUYA KIYOHIRO
MATSUMOTO NORIMASA
MATSUDA YOSHIO
