Diagnostic Experiment and Kinetic Model Analysis of Microwave CH4/H2Plasmas for Deposition of Diamondlike Carbon Films

Medium-pressure CH4/H2plasmas were generated in a discharge tube on the axis of a cylindrical 2.45-GHz-microwave TM011-mode-resonance cavity for chemical vapor deposition of diamondlike carbon films. Diamondlike carbon synthesis, plasma diagnostic measurements and kinetic model analyses were conducted to examine the correlation between plasma properties and film features. The characteristics of the calculated H-atom density of the excitation quantum level 4 agreed with those of the measured spectral intensity of the Hβ line. Consequently, high density ratios of C atoms to H atoms were required for deposition of diamondlike carbon. On the other hand, the density ratio of CH3radicals to H atoms was considered to be closely related to the hardness of deposited diamondlike carbons.