Relationship between Surface Cracks and Distribution of Crystalline Silicon Grains in RF-Sputtered β-FeSi2 Films

Applications in high-efficiency Si/β-FeSi2 heterojunction solar cells require the preparation of crack-free β-FeSi2 films on silicon. In this study, we obtained crack-free β-FeSi2 films on silicon(100) just substrate by RF-Sputtering using FeSi4 target even though we annealed the films at temperatures as high as 900 °C after deposition. These films contained numerous silicon crystalline grains because of using FeSi4 target. Furthermore, FeSix films were deposited on silicon(100) substrate 4° off the [110] direction at room temperature through the RF sputtering method using an FeSi3 target. The film annealed at 900 °C also contained a large amount of silicon. Different from the films on silicon(100) just substrate, however, the film developed cracks on its surface.