TRANSISTOR IN SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

摘要

A transistor of a semiconductor device and a manufacturing method thereof are provided to reduce defects by forming an epitaxial SiGe layer of high Ge density on an epitaxial SiGe layer of low Ge density. A gate is formed on a semiconductor substrate(20). A gate spacer(26A) is formed on each of both sidewalls of the gate. A recess is formed on source/drain regions of the semiconductor substrate by etching the semiconductor substrate corresponding to both sides of the gate spacer. A first epitaxial layer(28) including Ge is formed to bury the recess. A second epitaxial layer(28A) is formed on a boundary between the semiconductor substrate and the first epitaxial layer by performing a high-temperature oxidation process. The Ge density of the second epitaxial layer is higher than the Ge density of the first epitaxial layer.