High-speed Germanium-on-SOI lateral PIN photodiodes

We report the fabrication and characterization of high-speed germanium on silicon-on-insulator lateral PIN photodetectors. At an incident wavelength of 850 nm, 10 ×10-μm detectors with finger spacing S of 0.4 μm (0.6 μm) produced a -3-dB bandwidth of 29 GHz (27 GHz) at a bias voltage of -1 V. The detectors with S=0.6 μm had external quantum efficiency of 34% at 850 nm and 46% at 900 nm and dark current of 0.02 μA at -1-V bias.