FABRICATION OF AMORPHOUS DIAMOND FILMS

Amorphous diamond (a:D) is a hard, electrically insulating, inert and transparent form of carbon that has the sp(3) bond character of crysta lline diamond, but lacks a long-range ordered structure. Using our fil tered cathodic are system, we have produced a:D films at room temperat ure that demonstrate Vickers hardness above 8000 H-v, hydrogen content below 0.1%, density of 2.7 +/- 0.3 g cm(-3), and adhesion on tungsten carbide and silicon substrates above 70 MPa. The fine structure of a: D was characterized by transmission electron microscopy (TEM) and elec tron diffraction. TEM showed no evidence of any ordered structure down to 1 nm. Unlike natural diamond or diamond-like carbon, a:D has a fla t transmission spectrum from 0.8 to over 50 mu m, which is due to its amorphous nature and the lack of hydrogen. Also, we determined the ind ex of refraction of our a:D to be 2.47-2.57. The thermal diffusivity o f a:D has been measured and reported for the first time. We have lower ed the intrinsic stress in the films by the use of bias and the inclus ion of impurity atoms, and produced films up to 8 mu m thick on carbid e tool bits. In addition, a molecular dynamics code has been used to m odel this material.