Properties of GaAs/Al0.53Ga0.47As Avalanche Photodiode with Superlattice Fabricated by Molecular Beam Epitaxy

Abstract
A GaAs/AlGaAs APD with superlattice, exhibiting low dark current and large photocurrent multiplication characteristics, has been successfully fabricated by MBE. Dark currents were as low as 2.1×10-6 A/cm2 for a multiplication factor of 30. A study of the influence of oval defects on APD characteristics showed that no one-to-one correlation was found between oval defects and fatal diode deterioration. The ionization rate ratio, β/α, estimated from multiplication noise measurement, was less than 0.6–0.8. MBE is a useful technique for fabricating high performance APDs.