Influence of hydrogen supply on Mo(C,N) films synthesized by plasma-enhanced chemical vapor deposition using bis(tert-butylimido) bis(dimethylamido) molybdenum

Abstract Complex composites of Mo(C,N) are deposited at temperatures of 150°C and a working pressure of 1.3 Pa by plasma-enhanced chemical vapor deposition using bis(tert-butylimido) bis(dimethylamido) molybdenum as precursor, argon as carrier gas to transport the vapors of the liquid metal–organic precursor at 80°C, and hydrogen gas as reactant. The effect of hydrogen as reactive gas in the deposition process is investigated. For plasma generation in the plasma cleaning and deposition process, pulsed DC plasma is utilized at a negative voltage of 600 V with a frequency of 150 kHz and a pulse reversal time of 1 μs. As a result, hydrogen ambient decreases the deposition rate and surface roughness and increases the hardness of the films. Under the flow rate condition of hydrogen gas over 300 sccm, the hardness reaches high values over 26 GPa, and the adhesion is over 30 N. X-ray diffraction spectroscopy measurements reveal hexagonal phased molybdenum carbide as the preferred crystallization of the Mo(C,N) films, and nanocrystalline molybdenum nitride is mixed with the molybdenum carbide. Analysis of the chemical binding of the Mo(C,N) films by X-ray photoelectron spectroscopy and Raman spectroscopy shows that the dominant binding state is the molybdenum carbide, amorphous graphitic carbon and carbon nitride composites are identified from the evaluation of the binding energy of carbon atoms.