Evaluation of thin films fabricated by low energy direct ion beam deposition for soft X-rays

The amorphous structure and the surface roughness of carbon films fabricated by low energy direct ion beam deposition were evaluated as a function of ion energy. The amorphous structure was evaluated by the ordering factor, which was defined as a root-mean-square value of the correlation function of the RHEED pattern. The surface roughness was measured using STM and a stylus surface profiler. The ordering factor and surface roughness drastically changed as ion energy was increased from 20 to 140 eV. From this experiment, we found that carbon films fabricated at 100 eV have the smallest ordering factor and the smallest surface roughness. (orig.)