Abstract: This invention relates to a method of manufacturing a MOSFET with LDD regions, high integrated semiconductor, wherein a photoresist pattern for a source/drain implant mask is formed to sufficiently cover the part where the edge between field oxide layer and LDD regions are crossed. As a result, at the place damaged from the formation of spacer at the side wall of gate electrode, high concentrated impurity should not be implanted so as to form the source/drain region within LDD regions. Consequently, this invention prevents the weakening of breakdown voltage or increase of leakage current.

Abstract: An LDD transistor, preventive of the weakening of source/drain junction breakdown voltage and the increase of junction leakage current, and a method for the fabrication of the same. The LDD transistor is comprised of: a field oxide film formed on a predetermined portion of a semiconductor having a low density ion-implanted region therein, the field oxide film having a damaged portion; a gate electrode formed over the field oxide film; an insulating film formed over the gate electrode; a gate polyoxide film resulting from the oxidation of the side wall of the gate electrode; a spacer insulating film formed at the side wall provided by the gate polyoxide film and the insulating film atop the gate polyoxide film; a pad polysilicon film deposited over the insulating film, spacer oxide film, the low density ion-implanted region and the field oxide film; and a high density ion-implanted region formed below the pad polysilicon film, being confined within the low density ion-implanted region.