A semiconductor device has: a semiconductor substrate made of a first semiconductor material; an n-channel field effect transistor formed in the semiconductor substrate and having n-type source/drain regions made of a second semiconductor material different from the first semiconductor material; and a p-channel field effect transistor formed in the semiconductor substrate and having p-type source/drain regions made of a third semiconductor material different from the first semiconductor material, wherein the second and third semiconductor materials are different materials. The semiconductor device having n- and p-channel transistors has improved performance by utilizing stress.