MOS CAPACITOR AND MANUFACTURE THEREOF

PURPOSE:To obtain an MOS capacitor having a small size and a large capacity to take an electrostatic capacity in a large range by providing a semiconductor substrate having many grooves on its surface, a dielectric oxide film formed on the substrate and electrodes formed on the film. CONSTITUTION:The surface area of a semiconductor substrate 11 made of a silicon substrate is set, for example, to desired value by many grooves 11a formed in a stripe or lattice shape by etching. A dielectric oxide film 13 formed of a silicon oxide film (SiO2, epsilonapprox.=3.0-3.5) formed in a desired thickness by thermally oxidizing the substrate. Further, electrodes 14 formed by patterning are provided to become a desired size. Since the surface area of the substrate can be increased to be controlled by the etching degree of the grooves, the electrostatic capacity of an MOS capacitor can be arbitrarily set, and the size of the electrodes can be reduced as the surface area increases.