Method for forming a transistor with reduced source/drain series resistance

Abstract

A method for forming a transistor in integrated circuits is disclosed. The method includes the following steps. A substrate is first provided. An insulating layer is then formed on the substrate. A conductor layer is formed on the insulating layer. Subsequently, a patterned photoresist layer is formed on the conductor layer. Next, an etch process is used to etch the conductor layer which has a sidewall. The patterned photoresist layer is then removed. After forming a liner layer on the sidewall of the conductor layer, a lightly doped drain is formed on and in the substrate. Then, a spacer is formed on the liner layer. Thereafter, a proper process is used to introduce ions into the lightly doped drain, and then a source/drain region is completed. The steps with follow include annealing the source/drain region and removing the spacer. Subsequently, an epi-silicon layer is formed on the lightly doped drain region, the source/drain region and the top surface of the conductor layer. Finally, the epi-silicon layer is treated with a salicidation process to form a salicide layer.