Method of fabricating metal oxide semiconductor transistor with lightly doped impurity regions formed after removing spacers used for defining higher density impurity regions

Abstract

In a method of fabricating a metal oxide semiconductor (MOS) transistor with a lightly doped drain (LDD) structure without spacers, gate electrodes and spacers are formed on a semiconductor substrate. A high density source/drain region is formed using the gate electrodes and the spacers as masks. A low density source/drain region is formed after removing the spacers. It is possible to reduce the thermal stress of the low density source/drain region by forming the high density source/drain region before the low density source/drain region is formed and to increase an area, in which suicide is formed, by forming a structure without spacers. Also, it is possible to simplify processes of fabricating a complementary metal oxide semiconductor (CMOS) LDD transistor by reducing the number of photoresist pattern forming processes in the method.