SEMICONDUCTOR DEVICE

摘要

Provided is an integrated circuit having a LOCOS-drain type MOS transistor mounted thereon in which, even in the case of poor pattern formation, a withstand voltage is not lowered and a poor withstand voltage does not result. A drain oxide film thicker than a gate oxide film is formed on an active region on a drain side of the LOCOS-drain type MOS transistor, to thereby prevent the withstand voltage of the MOS transistor from being lowered even if the gate electrode reaches the active region on the drain side.

主权项

1. A semiconductor device including a MOS transistor, the MOS transistor comprising:
a gate oxide film formed on a surface of a channel region; a LOCOS oxide film thicker than the gate oxide film, the LOCOS oxide film being formed on a drain side successively with a formation of the gate oxide film; and a drain oxide film thicker than the gate oxide film and thinner than the LOCOS oxide film, the drain oxide film being formed successively with a formation of the LOCOS oxide film on a surface of an active region on the drain side of the MOS transistor beyond the LOCOS oxide film on a side opposite to the channel region.