Abstract: The on-resistance per chip area of a horizontal power MOSFET is reduced. In the horizontal power MOSFET in accordance with the present invention, low resistance penetrating conductive zones penetrating from a semiconductor surface in a p-type semiconductor zone on a low resistance p-type semiconductor substrate connected to an outer source electrode up to the p-type semiconductor zone are formed, and two or more n-type drain zones electrically connected to drain electrodes are formed in a semiconductor zone surrounded by the low resistance penetrating conductive zones, and an outer drain zone is provided on an active zone.

Abstract: The on-resistance per chip area of a horizontal power MOSFET is reduced.

Abstract: Plural grooves are formed in a main surface of semiconductor layers on semiconductor substrate, and gate layers connected to a gate electrode are formed in the plural grooves through a gate insulating film, and then a body diffusion layer is formed between the gate layers, and afterwards, a source diffusion layer connected to a source electrode and a source diffusion layer connected to a source electrode are formed in an identical process.