Avalanche multiplication and excess noise characteristics in antimony-based avalanche photodiodes

Avalanche photodiodes (APDs) capable of operating at telecommunication wavelengths usually utilize an InGaAs absorber and a multiplication region of InP or InAlAs. Since the electron and hole ionization coefficients (α and β respectively) in these multiplication regions are very similar they suffer from high excess noise, limiting their sensitivity. In recent years, there have been a number of reports of Sb containing III-V semiconductor alloys that appear to show very low excess noise characteristics, similar to or better than that obtained in silicon. These reports show that AlInAsSb grown on GaSb appears to show a β/α ratio of ~0.015. Both AlAsSb and Al_0.85Ga_0.15As_0.56Sb_0.44 grown lattice matched on InP also show β/α values that vary from 0.005-0.01. The exception to this appears to be AlGaAsSb grown lattice matched on GaSb where a β/α ratio of ~2.5 has been seen. This paper reviews the published results in this area.