Method of forming source/drain regions in semiconductor devices

Abstract

A method of forming source/drain regions in semiconductor devices. First, a substrate having at least one gate structure is provided. Next, first, second, and third insulating spacers are successively formed over the sidewall of the gate structure. Subsequently, ion implantation is performed on the substrate on both sides of the gate structure using the third insulating spacer as a mask to form first doping regions. After the third insulating spacer is removed, ion implantation is performed on the substrate on both sides of the gate structure using the second insulating spacer as a mask to form second doping regions serving as source/drain regions with the first doping regions. Finally, after the second insulating spacer is removed, ion implantation is performed on the substrate on both sides of the gate structure using the first insulating spacer as a mask to form third doping regions, thereby preventing punchthrough.