A Fast and Accurate Method of Extracting Two Critical Device Parameters of SAGCM InP/InGaAs Avalanche Photodiodes

Separate absorption, grading, charge, and multiplication (SAGCM) InP/InGaAs avalanche photodiodes (APDs) are the preferred candidates in long haul fibre optical telecommunication systems. In this paper, we report a simple, fast, accurate, and non-destructive technique for extracting of two critical device parameter - multiplication layer thickness Xd and charge sheet density ¿, using punchthrough and breakdown voltages obtained from DC measurements. Impact ionization in InGaAs absorption layer is considered and we show that it can be neglected if the breakdown voltages are not high. We consider in detail the uncertainties from all sources, and conclude that the accuracy for Xd is ≪ 0.05 ¿m, and for ¿a is ≪ 3%.