The Effects of Femtosecond Laser Irradiation and Thermal Annealing on the Optoelectronic Properties of Silicon Supersaturated with Sulfur

Electrochemical capacitance-voltage profiling, Raman and absorption spectroscopy measurements are employed to characterize the electronic and optical properties of silicon supersaturated with sulfur above the equilibrium solubility limit. Silicon wafers are ion implanted with 50 keV ³²S⁺ to a dose of 1×10¹⁶ ions/cm² and subsequently irradiated by femtosecond pulses at a fluence of 0.2 J/cm², followed by thermal annealing at 825 K for 30 min. The spectral response of the photodiode fabricated from the laser-irradiated sample is also investigated. It is found that femtosecond laser irradiation and subsequent thermal annealing can electrically and optically activate the supersaturated sulfur dopant in silicon, as well as reduce the implantation-induced damage in the silicon lattice.