Correlation between impurities in Fe–Si amorphous layers synthesized by Fe implantation and photoluminescence property of β-FeSi2 precipitates in Si

Completely amorphous Fe–Si layers are formed by Fe implantation into Si substrate at a dosage of 5×1015 cm−2 using a metal vapor vacuum arc (MEVVA) ion source under 80 kV extraction voltage and cryogenic temperature. After thermal annealing, β-FeSi2 precipitates are formed in Si matrix. The influence of impurities in these amorphous Fe–Si layers on the photoluminescence (PL) from β-FeSi2 precipitates is investigated. PL is found to be significantly enhanced by optimizing the impurity concentration and annealing scheme. After 60 s of rapid thermal annealing (RTA) at 900 °C, β-FeSi2 precipitates in medium boron-doped Si substrate give the strongest PL intensity without boron out-diffusion from them.