Semiconductor device and method for fabricating the same

摘要

An element isolator is formed in a silicon substrate. A gate oxide film and a gate electrode are formed overlying the silicon substrate. Subsequently, a four-step large-tilted-angle ion implant is performed in which ions of nitrogen are implanted at an angle of tilt of 25 degrees, to form an oxynitride layer at each edge of the gate oxide film and to form a nitrogen diffusion layer in the silicon substrate. This is followed by formation of a lightly-doped source/drain region by means of impurity doping. A sidewall is formed on each side surface of the gate electrode, which is followed by formation of a heavily-doped source/drain region by impurity doping. The present invention provides an improved semiconductor device having high-performance, highly-reliable MOS field effect transistors and a method for fabricating the same.