Tailoring thin mesoporous silicon-tin films by radio-frequency magnetron sputtering

Thin Si1-xSnx films with 0 < x < 0.51 (at.%) have been deposited from Si and Sn targets by radio-frequency magnetron sputtering at vacuum pressures of 1 and 0.6 Pa. The different contents of Sn incorporation were achieved by varying the power applied to the Sn target (25, 50, 75 and 100 W) while maintaining a constant power of 400 W on the silicon target. The results showed that the films deposited at 1 Pa were more porous, in the mesoporous region, than the films deposited at 0.6 Pa. For the Sn concentrations lower than 28%, the films were amorphous. For higher Sn concentrations, the films were formed by a b-Sn nanocrystalline structure embedded in an amorphous matrix. The hardness values decreased with the increase in the Sn content in the films.