Method of fabricating metal oxide semiconductor field effect transistor

A method for fabricating a MOSFET, comprising:

• forming a germanium layer with a predetermined thickness by implanting germanium ions into a semiconductor substrate;
• etching an overlying portion of the semiconductor substrate disposed over the germanium layer to expose the germanium layer, wherein etching the overlying portion comprises etching the overlying portion by a wet etching process;
• forming an epitaxial layer doped with high concentration impurities on the exposed germanium layer;
• forming a gate structure on the epitaxial layer;
• forming source/drain regions in the semiconductor substrate;
• and
• forming a selective epitaxial layer on the source/drain regions, wherein the selective epitaxial layer is formed on a same horizontal plane with the gate structure.