Synthesis of Ge1–xSnx and Ge1–x–ySnxCy films by magnetron sputtering followed by laser annealing

Ge1–xSnx is a critically important material for creating direct-bandgap semiconductors integrated into silicon photonic platforms. However, the low equilibrium solubility of Sn in Ge and high mechanical strain in Ge1–xSnx films hinder their application. This work develops a cost-effective method for producing structurally stable Ge1–xSnx films with relatively high Sn content by incorporating carbon and evaluates the efficiency of laser annealing for crystallization. Amorphous films were deposited by magnetron sputtering and subjected to laser and thermal annealing. Laser annealing enables formation of films with substitutional Sn content up to 4.2 at.% and crystallite size ~30 nm, significantly exceeding thermal annealing results. Co-incorporation of carbon improves surface morphology.