Patent ID: 7755133

Claim:
A semiconductor device comprising: a semiconductor substrate having a cell region and a peripheral region; a cell active region formed in the cell region; a peripheral active region formed in the peripheral region, wherein the cell active region and the peripheral active region are defined by isolation regions; a first gate stack formed on the cell active region; a second gate stack formed on the peripheral active region; a cell epitaxial layer formed on an exposed portion of the cell active region and comprising an extending portion disposed on a first isolation region of the isolation regions; and, a peripheral epitaxial layer formed on an exposed portion of the peripheral active region and comprising an extending portion disposed on a second isolation region of the isolation regions, wherein the height of the peripheral epitaxial layer is greater than the height of the cell epitaxial layer, and the horizontal length of the extending portion of the cell epitaxial layer is shorter than the horizontal length of the extending portion of the peripheral epitaxial layer.