Electrical Properties of RF-Sputtered FeSi_x Films and Their Relationship to Phase Transition from ε-FeSi to β-FeSi₂ during Post-Annealing

Abstract

FeSi_x films were deposited on Si (100) substrates by RF-sputtering method using an FeSi₂ target and post-annealing was carried out at temperatures in the range of 400-900°C for 1~h in Ar ambient. Sheet resistance of the deposited films was measured by four-point probe method and crystallinity of the films was analyzed by X-ray diffraction (XRD) measurement. Sheet resistance and XRD measurements revealed that the Fe atoms near the FeSi_x/Si interface were diffused towards Si substrate and the bottom of the deposited film gradually transformed to β-FeSi₂ with increasing the annealing temperatures although the FeSi_x films annealed at temperatures from 500°C to 800°C contained both ε-FeSi and β-FeSi₂. The film annealed at 900°C was completely transformed β-FeSi₂. [DOI: 10.1380/ejssnt.2012.190]