Method for producing metal-oxide-semiconductor transistor

The invention discloses a method of making metal oxide semiconductor (MOS) transistor, comprising: providing a substrate and forming a gate structure on the substrate, and forming a skewed gap wall around the gate structure and forming a sacrifice gap wall around the skewed gap wall; forming plural extension layers on two sides of the gate structure, where the extension layers are outside the sacrifice gap wall and then removing the sacrifice gap wall and forming plural drain/source extension regions in the substrate outside the skewed gap wall and the extension layers. Thus, the high temperature of selective extension process can not destroy the source/drain extension regions.