Patent ID: 8329548

Claim:
A method of manufacturing a field transistor, comprising: sequentially forming an oxide layer and a mask layer pattern on a well region of a first conductivity type; using the mask layer pattern as an ion implantation mask to implant impurity ions of the first conductivity type into the well region; forming a photoresist layer pattern on portions of the oxide layer and the mask layer pattern; using the exposed portion of the mask layer pattern and the photoresist layer pattern as an ion implantation mask to implant impurity ions of a second conductivity type into the well region; removing the photoresist layer pattern; forming a field oxide layer in which a portion of the oxide layer is grown using the mask layer pattern as an oxide growth prevention layer while diffusing the impurity ions of the first and second conductivity types to form low concentration source/drain regions of the second conductivity type; forming high concentration source/drain regions of the second conductivity type on either side of the field oxide layer in the well region; forming a high concentration diffusion region of the first conductivity type so that the high concentration diffusion region of the first conductivity type is separated from the high concentration source region of the second conductivity type by a predetermined distance; and forming a gate conductive layer pattern on the field oxide layer.