PURPOSE: To establish reliable isolation between cells and to enlarge capacitor regions and thereby to realize enlarged capacity by a method wherein isolating regions are defined by grooves of two different widths for the formation of cells on a semiconductor substrate and a capacitor section is formed to extend along the sidewalls of an isolating region containing the wider groove.

CONSTITUTION: A capacitor section on a semiconductor substrate 1 consists of a portion A wherein an active region 2 is covered by a plate electrode 5 and its sidewall A', and stores signal electric charges. The signals are outputted to a contact 7 with the intermediary of a transfer gate 6. Isolation between capacitors is established by a second isolating region 4, that is, it is established by polycrystalline silicon 10 covered by a thick oxide film 9 and a channel stopper 15. Isolation between transistors is established by a first isolating region 3 incorporating a narrow groove w1. In the same way, the isolation is established by the polycrystalline silicon 10 covered by the thick oxide film 9 and the channel stopper 15. In this method, with a capacitor section extending along the side walls of the second isolating region 4 from a flat section, there is an increase in the storage of electric charges.