High-Performance Waveguided Ge-on-SOI Metal–Semiconductor–Metal Photodetectors With Novel Silicon–Carbon (Si : C) Schottky Barrier Enhancement Layer

We report the demonstration of waveguided germanium-on-silicon-on-insulator metal-semiconductor-metal (MSM) photodetectors with novel silicon-carbon (Si:C) Schottky barrier enhancement layer. Significant suppression of dark current (/dark) by ~4 orders of magnitude was achieved over a conventional MSM photodetector due to an enhanced hole Schottky barrier height of 0.52 eV. At an applied bias V
_A
of 1.0 V a -3-dB bandwidth of ~12 GHz at an incident wavelength of 1550 nm was demonstrated. Optical measurements performed at photon wavelengths lambda of 1520-1570 nm reveal a uniform spectral response and quantum efficiency of ~760 mA/W and ~60%, respectively, demonstrating an effective photodetection for the entire C-band spectrum range.