Method for fabricating MOS field effect transistor

摘要

A method of fabricating a MOS field effect transistor. A gate insulating film and a gate conductive film are formed on a semiconductor substrate. The gate conductive film is patterned to form a first gate conductive film having a thin thickness and a second gate conductive film having a thick thickness. An insulating film pattern is formed on a side wall of the second gate conductive film. The insulating film pattern is used as an etching mask to remove exposed portions of the first gate conductive film and the gate insulating film. An etch process is performed to remove the insulating film pattern and a portion of the gate insulating film under the first gate conductive film. An ion implantation process is performed using the first gate conductive film as an ion implantation buffer for a lightly doped impurity region to form a source/drain region.