Fast and efficient integrated silicon PIN-finger photodetector from ultraviolet up to near infrared

Results of an integrated silicon PIN-photodetector with structured anode fingers are presented. As an improvement to homogenous photodiodes, a structured detector for the visible range with anode fingers is shown. A PIN-design was realized to speed up the detector, avoiding slow carrier diffusion: the p⁺ doped finger-anode is arranged in a thick n⁺ low doped intrinsic region placed inside an n⁺ doped region. Due to this setup and a thick intrinsic region, a responsivity of R = 0.25 A/W (0.43 A/W) at a wavelength of 410 nm (660 nm) could be reached. The achieved bandwidth of the detector in the visible range is up to 3 GHz. The photodiode was realized in a modified 0.5 μm BiCMOS process.