Background and Objectives: Requirements and problems are formulated when creating cathode materials for high-current emission electronics. It has been shown that to create autocathodes with a current density of up to 100 A/cm2 and above, the development of new nanostructured carbon materials with a surface density of nanodiamond edges of not less than 106–108 cm-2 is necessary. Using a non-equilibrium low-pressure microwave plasma, the regions of regimes for obtaining carbon film coatings containing the diamond and graphite phases in various volume ratios are determined.