Patent ID: 6222235
Filing Date: 2001-04-24
Classification: H01L

Abstract:
A high-voltage MOSFET semiconductor device comprising:a source region and a drain region of a second conductivity type formed apart from each other on a surface of a semiconductor region of a first conductivity type and a channel forming region therebetween, said drain region having a high concentration drain portion and a low concentration drain portion, the low concentration drain portion interposed between the channel forming region and the high-concentration drain portion,a gate insulating film formed on the channel forming region constituted by the surface of the semiconductor region between the source region and the drain region,a gate electrode formed on the gate insulating film, anda substrate electrode region of a first conductivity type formed on the surface of the semiconductor region separated from the source region to provide a resistance between the source region and the substrate electrode,wherein the high concentration drain portion has a withstanding voltage that is lower than a predetermined voltage when the MOSFET semiconductor device is in an ON state and higher than the predetermined voltage when the MOSFET semiconductor device is in an OFF state, the predetermined voltage being about 30 volts, whereby the lower withstanding voltage in the ON state allows the reduction in size of the high-voltage MOSFET semiconductor device.