TWI801670B

The capacity of a MOS capacitor is increased. A semiconductor element includes a first semiconductor region, an insulation film, a gate electrode, and a second semiconductor region. The first semiconductor region is arranged on a semiconductor substrate and has a recess on the surface. The insulation film is arranged adjacent to the surface of the first semiconductor region. The gate electrode is arranged adjacent to the insulation film and constitutes a MOS capacitor with the first semiconductor region. The second semiconductor region is arranged adjacent to the first semiconductor region on the semiconductor substrate, formed in the same conductive type as the first semiconductor region, and supplies a carrier to the first semiconductor region when the MOS capacitor is charged and discharged.