Room Temperature 1.58 µm Photoluminescence and Electric Properties of Highly Oriented β-FeSi2 Films Prepared by Magnetron-Sputtering Deposition

Abstract

Continuous and highly oriented β-FeSi2 films were prepared on Si (111) substrates at 700–760°C by use of a RF magnetron sputtering deposition with a Fe target. An inserted low temperature (450°C) initial layer and post-annealing were effective in improving the crystal quality characterized by the widths of X-rays rocking curve (ω scan) and the photoluminescence intensity. As grown β-FeSi2 films with a full width at half maximum of 15 arcmin were obtained and 1.58 µm photoluminescence at room temperature was clearly observed from the 800°C annealed films. The as-grown films were p-type, with a hole concentration and a Hall mobility about 2×1018 cm-3 and 20 cm2/V·s respectively. A conduction type change took place after thermal annealing in N2 at 890°C for 20 hours, resulting in a electron concentration of 5×1016 cm-3 and a mobility up to 230 cm2/V·s, while a p-type conduction with a diminished hole concentration and a increased mobility, still remained after thermal annealing at 800°C.