DEPOSITION MECHANISMS FOR PROMOTING SP(3) BONDING IN DIAMOND-LIKE CARBON

Deposition of amorphous carbon from medium energy ion beams promotes sp3, diamond-like bonding. It is proposed that the sp3 bonding arises from an increased density, owing to carbon ions entering subsurface atomic sites. An optimum ion energy arises from a balance between the incident carbon ions having sufficient energy to penetrate the surface atomic layer, while minimizing any excess energy dissipated in a thermal spike which can anneal out the density increment.