Tailored Molybdenum Carbide Properties and Graphitic Nano Layer Formation by Plasma and Ion Energy Control during Plasma Enhanced ALD

We demonstrate the extensive study on how film density and crystallinity of molybdenum carbide ($MoC_{x}$) can be tailored during plasma-enhanced ALD (PEALD) by controlling either the plasma exposure time or the ion energy. We investigated $MoC_{x}$ films grown using $Mo(^tBuN)_2(NMe_2)_2$ as the precursor and $H_2/Ar$ plasma as the co-reactant at temperatures between 150°C and 300°C. We discover a threshold for graphitic layer formation at high mean ion energies during the PEALD cycle. The supplied high energy dose allows for hybridised $sp^{2}$ carbon bonds formation, similar to high temperature annealing. The graphitisation of the $MoC_{x}$ surface takes place at temperature of 300$^{\circ}C$. The graphitic film show a (101) plane diffraction peak with dominant intensity in XRD, and a typical $sp^{2}$ C1s peak along with carbidic metal in XPS measurements. Surface roughness of the film lowers significantly at the graphitisation regime of deposition. This low temperature graphitisation by high energy plasma ions during PEALD shows a great promise to advancing graphene and graphite composites at low temperature by PEALD for future applications.