Control of crystal phase in Fe/Si films by using thin film Zone Melting Crystallization

摘要

For the development of a new solar cell material, β-iron silicide (β-FeSi_2) films were fabricated by using the following two techniques involving the thin film Zone Melting Crystallization (ZMC) method. First, β-FeSi_2 was formed by post-annealing ZMC films composed of α-FeSi_2. The phase transition from α -FeSi_2 to β-FeSi_2 was induced by the post-annealing and promoted with Cu. Second, β-FeSi_2 was directly formed from the melt without post-annealing by adjusting the power of upper and lower heaters in the ZMC. Results showed that (1) crystal phase of the Fe/Si films could be controlled by adjusting the power of each heater in the ZMC, (2) Cu promoted formation of β-FeSi_2 from amorphous in addition to promoting phase transition from α-FeSi_2 to β-FeSi_2, and (3) crystal phase of ZMC films depended on the dispersion of Cu in the films.