US Patent 7347228 Method of making semiconductor devices

A method for fabricating semiconductor device is provided. A high stress layer formed on, under or on both sides of the transistors of the semiconductor device is employed as a cap layer. A specific region is then defined through photo resistor mask, and the stress of the region is changed by ion implanting. Therefore, compressive stress and tensile stress occur on the high stress layer. According the disclosed method, the high stress layer may simultaneously improve the characteristics of the transistors formed on the same wafer. Further, the mobility of the carriers of the device is enhanced.