Semiconductor structures is provided. The semiconductor structure includes a semiconductor substrate having at least one first region, a plurality of second regions and a plurality of third regions; at least one second fin formed on one second region of the plurality of second region; at least one third fin formed on one third region of the plurality of third regions; a first epitaxial layer formed in the at least one first fin; and a second epitaxial layer formed in the at least one second fin and the at least one third fin.