Abstract: A semiconductor process includes the following steps. A gate structure is formed on a substrate. A main spacer is formed on the substrate beside the gate structure. A source/drain is formed in the substrate beside the main spacer. After the source/drain is formed, an epitaxial structure is formed in the substrate beside the main spacer. A gate structure may be respectively formed in a first area and a second area of a substrate. A main spacer is formed on the substrate respectively beside the two gate structures. A source/drain is formed in the substrate respectively beside the two spacers. After the two source/drains are formed, an epitaxial structure is formed in the substrate respectively beside the main spacers.

Abstract: A semiconductor process includes the following steps. A substrate is provided. A gate structure is formed on the substrate. A spacer is formed on the substrate beside the gate structure. The spacer includes a first spacer and a second spacer located on the external surface of the first spacer. A first etching process is performed to etch and form at least a recess in the substrate beside the spacer and entirely remove the second spacer. The etching rate of the first etching process to the first spacer is lower than the etching rate of the first etching process to the second spacer. An epitaxial layer is formed in the recess.