Patent ID: 6472710
Filing Date: 2002-10-29
Classification: H01L

Abstract:
A field MOS transistor comprising:a semiconductor substrate of first conductivity type; an epitaxial layer of second conductivity type formed on the semiconductor substrate; a field insulating film formed on the epitaxial layer; a heavily-doped isolation layer of first conductivity type formed in a predetermined location on the semiconductor substrate, the heavily-doped isolation layer surrounding an island region of the epitaxial layer; a lightly-doped isolation layer of first conductivity type formed on the heavily-doped isolation layer, the lightly-doped isolation layer, along with the heavily-doped isolation layer, surrounding the island region of the epitaxial layer; a channel formation region formed so as to be joined to a lower surface of the field insulating film, the channel formation region having substantially the same doping level as that of the lightly-doped isolation layer; a gate electrode formed on the field insulating film above the channel formation region; and a source region and a drain region of second conductivity type respectively formed within the island region of the epitaxial layer and on the opposite sides of the channel formation region.