Epitaxial silicon n + -p-π-p + avalanche photodiodes for optical fiber communications at 800 to 900 nanometers

摘要: Silicon n+-p-π-p+avalanche photodiodes, having high speed (1 ns response time), low noise and current gain, have been developed for optical fiber communications. These detectors provide a 16 dB improvement in sensitivity over nonavalanching photodiodes receivers operating at 825 nm 44.7 Mbit/sec. To facilitate fabrication on large diameter wafers, achieve uniform avalanche obtain quantum efficiencies greater than 90% 800 to 850 nm, the are constructed from 50 µm thick, resistivity epitaxial silicon. At an average gain of 100, their resulting excess factor is only 4 6 times shot limit. Low dark currents good reliability achieved through use guard rings, channel stops, bulk surface gettering, dielectric passivation field plates.