Primary reaction processes in the deposition of diamond-like carbon films by photon-enhanced CVD of methane using a windowless hydrogen lamp

Thin films of diamond-like carbon have been deposited using a photon-enhanced CVD method. Initial results have been reported previously. This paper investigates the possible mechanisms involved in film growth by electrical characterization of the plasma in the chamber, and by relating the variation in film growth rate to deposition pressure. The results indicate that the primary deposition mechanism is due to phyotolysis, with CVD due to diffusion of the hydrogen plasma from the lamp playing a lesser role. Material properties of the films have been studied by many methods, including Raman spectroscopy and elastic recoil detection analysis. These results are reported here and, in agreement with previous work, indicate that the films produced are semiconducting hydrogenated amorphous carbon, with hydrogen concentrations of between 35 and 45 at.%.