Infrared absorption and sub-bandgap photo-response of hyperdoped silicon by ion implantation and ultrafast laser melting

In the field of current silicon (Si)-based photonics, photodetectors are required to detect the light in near-infrared region (>1100 nm), at the same time, they should meet the requirements of high sensitivity, thermal stability, and good compatibility with CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology process. In order to extend the detection wavelength of Si to near-infrared region, introducing intermediate band (IB) into the bandgap of Si is an effective method, which can be realized by hyper-doping of deep-levels impurities. As nonequilibrium doping technique, ion implantation and pulsed laser annealing can make the concentration of impurities exceed the equilibrium solubility limit in Si by several orders of magnitude. In the past twenty years, the potential of hyper-doped Si as an IB material has aroused new interest in the field of infrared photodetection. In this review, we focus on the infrared absorption and infrared detection of hyper-doped Si by ion implantation and pulsed laser annealing. The infrared absorption mechanism, and influencing factors of infrared absorptance for hyper-doped Si with chalcogens and transition metals have been emphasized. For infrared photodetectors, the latest research on the responsivity and external quantum efficiency of photodetectors based on hyper-doped Si has been reviewed. Finally, some suggestions have been provided to improve the infrared absorption and performance of photodetectors. This work summarizes the latest progress of infrared absorption and infrared photodetectors by ion implantation and pulsed laser annealing, which will broaden the application of Si-based infrared photodetectors in the Si-based photonics integration.