Dark current and breakdown analysis in In(Al)GaAs/InAlAs superlattice avalanche photodiodes

We studied and compared the reverse-bias characteristics of In(Al)GaAs/InAlAs Superlattice Avalanche Photodiodes (SL-APDs) for three types of different well structures. Dark current characteristics were drastically improved in the InAlGaAs quaternary well structure application, compared with InGaAs wells. In the InAlGaAs quaternary well SL-APDs, we observed, for the first time, a linear relation between dark current and multiplication factor. A multiplied dark current of 2.0 x 10(-4) A/cm(2) was the lowest values for the SL-APDs. We also confirmed the temperature coefficient of breakdown voltage to be about 3.4 x 10(-4) K-1. This small temperature dependence suggests a distinctive SL-APD avalanche mechanism due to the contribution of large conduction band discontinuity.