Merged source drain epitaxy

A semiconductor device such as a FinFET includes a plurality of fins formed upon a substrate and a gate covering a portion of the fins. Diamond-shaped volumes are formed on the sidewalls of the fins by epitaxial growth which may be limited to avoid merging of the volumes or where the epitaxy volumes have merged. Because of the difficulties in managing merging of the diamond-shaped volumes, a controlled merger of the diamond-shaped volumes includes depositing an amorphous semiconductor material upon the diamond-shaped volumes and a crystallization process to crystallize the deposited semiconductor material on the diamond-shaped volumes to fabricate controllable and uniformly merged source drain.