MICROSTRUCTURE OF MOLYBDENUM DISILICIDE SILICON-CARBIDE NANOCOMPOSITETHIN-FILMS

Composite thin films of molybdenum disilicide-silicon carbide (MoSi2-S iC) have been deposited via rf magnetron sputtering onto molybdenum su bstrates. An intermediate layer was deposited in the presence of nitro gen gas and evaluated as a potential diffusion barrier layer. The comp osite films have been characterized using X-ray diffractometry, scanni ng electron microscopy, transmission electron microscopy, and Auger el ectron spectroscopy. The as-deposited films were amorphous but crystal lized into nanometer-sized grains after annealing under vacuum at 1000 degrees C for 30 min. There was a significant amount of interdiffusio n between the film and substrate, which resulted in the formation of s ubsilicides such as Mo5Si3 and MoSi3, as well as Mo2C. The films that were deposited via reactive sputtering in a nitrogen ambient were amor phous in both the as-deposited and annealed conditions. Significantly fewer second phases were detected with the presence of the intermediat e Layer, which suggests the potential use of the nitrided (MoSixNyCz) layer as a high-temperature diffusion barrier layer for the silicon an d carbon.