Large-area Geiger-mode avalanche photodiodes for short-haul plastic optical fibre communication

Large-area Geiger-mode avalanche photodiodes (GMAPs) that are designed to be compatible with a 1.5 μm CMOS and silicon-on-insulator (SOI) CMOS process are presented here as candidate detectors for use in optoelectronic integrated circuits (OEICs). The photodetectors have 250 μm and 500 μm diameter active areas with 20 μm virtual guard ring overlaps. The GMAPs have a breakdown voltage of -30 V and will be biased below breakdown in avalanche mode. The diodes' junction capacitances at 5 V reverse bias are 11.66 pF and 41.71 pF respectively and 4.99 pF and 17.95 pF respectively at 27 V reverse bias. The 250 μm photodiode has a calculated bandwidth of 454 MHz when biased at -5 V while the 500 μm photodiode has a calculated bandwidth of 142 MHz when biased at -5 V calculated using small-signal equivalent circuits for the devices.