Control of the Crystal Phase in Fe/Si Films by Using Thin Film Zone Melting Crystallization

Abstract

For the development of a new solar cell material, b-iron silicide (b-FeS2) films were fabricated by using the following two techniques involving the thin film Zone Melting Crystallization (ZMC) method. First, b-FeSi2 was formed by post-annealing ZMC films composed of a-FeSi2. The phase transition from a-FeSi2 to b-FeSi2 was induced by the post-annealing and promoted with Cu. Second, b-FeSi2 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 b-FeSi2 from amorphous in addition to promoting phase transition from a-FeSi2 to b-FeSi2, and (3) crystal phase of ZMC films depended on the dispersion of Cu in the films.