Low-Temperature Synthesis of Crack-Free β-FeSi₂ Films

Abstract

FeSi_x films were deposited on Si (100) substrates by RF-sputtering method at room temperature using FeSi₂ and FeSi₃ targets. After deposition, post-annealing was carried out at temperatures in the range of 500-900℃ in a quartz furnace for 1 h in Ar ambient. XRD measurements revealed that an annealing temperature of 900℃ was required for the FeSi_x films deposited with an FeSi₂ target to be completely transformed to β-FeSi₂ phase and that the FeSi_x films deposited with an FeSi₃ target were completely transformed to β-FeSi₂ phase after annealing at as low as 500℃. Although the FeSi_x film deposited with an FeSi₂ target was transformed to β-FeSi₂ phase after annealing at 900℃, it had many cracks on the surface due to high temperature annealing. On the other hand, the β-FeSi₂ film deposited with an FeSi₃ target had no cracks on the surface after annealing at 500℃. In summary, crack-free β-FeSi₂ films on silicon were successfully obtained by controlling the composition of a sputtering target.