Effect of Si on the Electronic Structure of Sputter-Deposited C Films: An Electron Spectrocopy Study

This work reports on the effect of Si addition on the structure of C films. C films were sputter deposited from a graphite target on a Si substrate, while Si-containing films were obtained by co-sputtering of Si and graphite. To investigate the effect of Si on the structure of the films, the following approach was taken: – the temperature evolution of pure C films was followed in the range from RT to 673K; – at a temperature of 573K, pure C films were compared to Si-containing ones. The samples' electronic structure was studied via VB Photoemission and line-shape analysis of the C KVV Auger transition, while the film chemical structure was checked by considering the C1s peak: all these signals were excited by monochromated Al Ka radiation. The sample composition across the whole film was followed by electron excited Auger sputter depth-profiling. It was found that C films deposited at RT exhibit pronounced diamond-like characteristics, while a trend towards a graphite-like character was observed with increasing deposition temperature. Quite interestingly however, Si was found to markedly change this evolution by preventing the C films from degrading towards a graphite-like structure at high deposition temperatures