Dynamic MC simulations of diamond-like carbon film synthesis by plasma-based ion implantation

By plasma-based ion implantation (PBII) such as low-energy ion beam implant ation in plasma, ion beam assisted deposition, and plasma immersed ion impl antation, a diamond-like carbon (DLC) him is synthesized. The structure of the DLC film can be characterized by the hydrogen concentration and the rel ative fractions of sp(2)- and sp(3)-bonded carbon. The energy of the imping ing ion plays a crucial role for the film structure and thereby the mechani cal, electrical and optical properties of the film. Dynamic Monte Carlo sim ulations with the binary collision approximation have been applied to the s ynthesis of DLC films by PBII. It was assumed that energetic CH3+ ions and CH3 radicals are incident on the surface alternately. The incident molecula r ions dissociated into its individual atoms when colliding with the surfac e. The radicals adsorbed on the surface are dissociated by the binary colli sions with the impinged atoms and a part of hydrogen atoms are released fro m the surface. It is assumed that only the atoms receiving enough energy to overcome the surface barrier enter the solid. Release of the displaced hyd rogen atoms after the subsequent collision cascade is also assumed. The rel ative fraction of carbon atoms in the sp(2)- and sp(3) state were estimated by setting different displacement threshold energy for each state. Effects of the ion/neutral arrival ratio and the ion energy on the deposition rate and on the depth profile of the hydrogen content and the sp(3)/sp(2) ratio in the deposited film are presented. (C) 2001 Elsevier Science B.V. All ri ghts reserved.