PURPOSE: To accumulate double information charges with the same capacitor area with a single crystal layer as one electrode of the capacitor by a method wherein the single cyrstal layer equal to a substrate and another insulation film are superposed on the insulation film at a part of the semiconductor substrate.

CONSTITUTION: An SiO2 thick film 105 is selectively formed by superposing a single crystal Si 103 on the SiO2 film 102 provided partially on the Si substrate 101. It is covered with an SiO2 film 106, and then an N+ layer 109 is formed by applying a resist mask 107, ion-implantation and heat treatment. A doped poly Si electrode 110 and an SiO2 111 are superposed oppsingly on the layer 109, and an SiO2 106 is removed. Next, a gate oxide film 113 and a poly Si gate electrode 114 are provided, ion implantation is performed, resulting in the formation of an N layer 115, covered with a PSG116, and then an Al wiring 117 is laid in connection ti the N layer 115. This constitution enables the capacitor part to be of a structure of halving and superposition; the substrate 101 and the poly Si electrode 110 are determined as opposed electrodes, and the area of 1/2 of normal one is enough to obtain a constant capacity value.