Formation of Cu₁₅Si₄/Si Nanophase Films on Silicon Surfaces

We report on the formation of copper silicide nanofilms using different magnetron sputtering modes. Copper silicide thin films were formed by sputtering Cu onto a Si(111) surface heated to 467oC in high vacuum using the mid-RFMS method at a frequency of 100 kHz and a D=70% efficiency. The thickness of the resulting heteroepitaxial Cu/Cu15Si4/Si film was measured using SEM. Also, a Cu15Si4 film was formed by thermally annealing Cu/Si(111) nanofilms in a vacuum at 800 K for 1.5 hours using the DCMS method. The thickness and surface morphology of the obtained samples were studied using SEM. The formation of silicide films is confirmed by the results of energy-dispersive spectra. The formation of a copper (Cu) silicide film depends on the copper crystal size and substrate temperature, and at 467℃, a 75 nm-thick Cu15Si4 film was formed under a 130 nm-thick copper layer. These findings provide new insights into the mechanisms governing copper-silicon interface reactions and highlight the potential of copper silicide nanofilms to improve the performance of metal-oxide-semiconductor transistors and high-speed integrated circuits.

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