Near-infrared waveguide-based nickel silicide Schottky-barrier photodetector for optical communications

Integrated silicon-on-insulator waveguide-based silicide Schottky-barrier photodetectors were fabricated using low-cost standard Si complementary metal-oxide-semiconductor processing technology. The thin epitaxial $\mathrm{Ni}{\mathrm{Si}}_2$ layer formed by solid-state Ti-interlayer mediated epitaxy on the top of Si-waveguide absorbs light propagating through the waveguide effectively and exhibits excellent rectifying property on both $p\text{-}\mathrm{Si}$ and $n\text{-}\mathrm{Si}$ . $\mathrm{Ni}{\mathrm{Si}}_2∕p\text{-}\mathrm{Si}$ detectors with tapered geometry demonstrate dark current of $\sim 3.0\mathrm{nA}$ at room temperature, responsivity of $\sim 4.6\mathrm{mA}∕\mathrm{W}$ at wavelengths ranging from $1520\text{to}1620\mathrm{nm}$ , and $3\mathrm{dB}$ bandwidth of $\sim 2.0\mathrm{GHz}$ . The approaches for further improvement in responsivity are addressed.