US Patent 7449374 Methods of manufacturing semiconductor devices with rotated substrates

Integrated circuits are oriented on a substrate at an angle that is rotated between 5 to 40 degrees from a direction parallel or perpendicular to a preferred crystalline plane direction, such as the cleavage plane, of the substrate. Parameters such as stress and mobility of transistors may be optimized by adjusting the angle of rotation of the substrate. For a rotated substrate CMOS device design, other stress control measures may be used, such as a stress control or tensile liner, over an NMOS transistor, PMOS transistor, or both, to further adjust the stress and improve performance.