Carbon

The diversity of the non crystalline forms of carbon is being revealed by investigations into its synthesis from plasmas. A major class of disordered carbons is being manufactured from the intense plasmas of arc discharges. The properties of the material produced depend on the temperature of growth and the energy of the depositing species. In a recently completed survey across the complete parameter range, we have compiled the first comprehensive phase diagram for carbon synthesis.

We now have the ability to control the orientation of graphene sheets in thin films by deposition from cathodic arc. Electronic applications of these materials are diverse, from vertical interconnect arrays (VIAs) to heat sink encapsulation materials.

Tetrahedral amorphous carbon is the densest and most electrically insulating form with more than 60% tetrahedrally bonded carbon sites. Hard, smooth, stable, chemically resistant, wear resistant and electrically insulating it is finding many applications as a thin film coating.

Snapshots of a simulation in which 40 eV atoms are deposited onto a ta-C substrate. Infrequent events are activated using the parameters Tact = 2000 K and tact = 1 ps. (a) The initial substrate, consisting of ta-C attached to diamond; (b) after 120 atoms have been deposited; (c) after 200 atoms have been deposited (oriented growth commences around the 160 atom mark); (d) the final structure (500 atoms deposited).