Semiconductor device and method of manufacturing same

摘要

After a field oxide film is formed on a P-type semiconductor substrate, ion implantation of boron is carried out with respect to a whole surface of the substrate so that a channel stopper layer is formed. Then, a MOS FET is formed in an active region of the semiconductor substrate. Subsequently, ion implantation of phosphorus is carried out, by using a gate electrode of the MOS FET and the field oxide film as a mask, so that impurity layers which have the same type of conductivity as that of the channel stopper layer and has a concentration lower than that of the channel stopper layer are formed right under the source/drain regions of the MOS FET between the source/drain regions and the channel stopper layer.