Patent ID: 7871867
Filing Date: 2011-01-18
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device, comprising: a step of forming a well region of a first conductivity type in a semiconductor substrate; a step of forming a second drain region by ion-implanting impurities of a second conductivity type into a predetermined region of the well region; a step of forming a LOCOS oxide film at least in a predetermined region of a surface of the second drain region; a step of forming a third drain region covered with the second drain region at least at a lower part thereof by ion-implanting impurities of the second conductivity type into a region including a region under the LOCOS oxide film wherein at least some of the impurities are injected through the LOCOS oxide film in the step of forming the third drain region; a step of forming gate insulation film adjacent to the LOCOS oxide film on a surface of the well region; a step of forming a gate electrode across the gate insulation film and the LOCOS oxide film; and a step of forming a source region and a first drain region in the well region and the second drain region, respectively, by ion-implanting impurities of the second conductivity type while using the gate electrode and the LOCOS oxide film as masks.