Low temperature synthesis of Mo2BC thin films

Abstract Emmerlich et al. [J. Phys. D: Appl. Phys. 2009, p42] reported the formation of Mo 2 BC coatings at a substrate temperature of 900 °C by combinatorial magnetron sputtering. This synthesis temperature limits the choice of substrate materials severely. Here, utilizing high power pulsed magnetron sputtering (HPPMS), the synthesis temperature was reduced to 380 °C, while the measured elastic modulus and lattice parameters of the as-deposited films are consistent with ab-initio data. Since the crystallization of amorphous Mo 2 BC powder was observed at 820 °C the HPPMS plasma was analyzed to identify the cause of the significantly reduced synthesis temperature. The measured ion current at the substrate and the ion energy distributions are consistent with the notion that energetic ion bombardment of film forming ions as well as Ar + during HPPMS enables surface diffusion and, hence, causes the substantial decrease of the formation temperature of crystalline Mo 2 BC to 380 °C reported here. Thus, low temperature synthesis of Mo 2 BC is surface diffusion controlled. The synthesis strategy reported here greatly expands the range of technologically interesting substrate materials for application.