CMOS TRANSISTORS AND FABRICATION METHOD THEREOF

A method is provided for forming CMOS transistors. The method includes providing a semiconductor substrate having at least one first region and at least one second region; and forming a first gate in the first region and a second gate in the second region. The method also includes forming first offset spacers made of nitrogen-contained material on side surfaces of the first gate and the second gate; and forming dummy spacers on the first offset spacers in the first region and a dummy spacer material layer covering the second gate and the semiconductor substrate in the second region. Further, the method includes forming SiGe stress layers in the semiconductor substrate at both sides of the first gate; and removing the first offset spacers, the dummy spacers and the dummy spacer material layer. Further, the method also includes forming second offset spacers on the first gate and the second gate.