Sub-micron high speed complementary metal-oxide semiconductor compatible metal-semiconductor-metal photodetector

Metal-semiconductor-metal photodetectors with electrode spacing of 0.5 mum have been fabricated on polysilicon films formed by low-pressure chemical vapor deposition. The detectors give a responsivity of 8 mA/W at 980 nm, and a 3-dB bandwidth of 1.5 GHz. Steady-state and transient photoresponse both appear to be limited by recombination and trapping at energy levels within the forbidden gap.