Submicron InGaAs/InP MSM photodetectors for operation at 1.55 mu m

The implementation of future high-speed optical communication networks operating in the 20-40 Gbit/s regime relies on the availability of correspondingly fast photodetectors for the 1.3-1.55 mu m wavelength range. Interdigitated InGaAs metal-semiconductor-metal (MSM) detectors in the InP material system are promising candidates for wideband photoreceivers due to their inherent lower specific capacitance as compared to p-i-n diodes. MSM photodetectors with submicron (0.3 mu m) feature size fabricated by electron beam lithography on 300 nm InGaAs absorption layer exhibit low dark current (<10 nA), a high external quantum yield (23%) and a frequency response up to 40 GHz at 1.55 mu m.