Silicon waveguide infrared photodiodes with >35 GHz bandwidth and phototransistors with 50 AW-1 response

SOI CMOS compatible Si waveguide photodetectors are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. Photodiodes have a bandwidth of >35 GHz, an internal quantum efficiency of 0.5 to 10 AW(-1), and leakage currents of 0.5 nA to 0.5 mu A. Phototransistors have an optical response of 50 AW(-1) with a bandwidth of 0.2 GHz. These properties are related to carrier mobilities in the implanted Si waveguide. These detectors exhibit low optical absorption requiring lengths from <0.3 mm to 3 mm to absorb 50% of the incoming light. However, the high bandwidth, high quantum efficiency, low leakage current, and potentially high fabrication yields, make these devices very competitive when compared to other detector technologies. (C) 2008 Optical Society of America