The deposition of a thick tetrahedral amorphous carbon film by argon ion bombardment

► Ar ion is used to bombard tetrahedral amorphous carbon (ta-C) films. ► sp2 bonds and sp2 clustering of ta-C film are increased by the Ar ion bombardment. ► The soft top layer and the hard bulk are formed in the ta-C film bombarded by Ar ion. ► The multilayer thick ta-C film can be deposited.