Two-dimensional gain profiles of InP/InGaAs separate absorption, grading, charge, and multiplication avalanche photodiodes modeled by a simplified stochastic approach

The two-dimensional (2D) gain profiles of InP/InGaAs separate absorption, g rading, charge, and multiplication (SAGCM) avalanche photodiodes (APDs) hav e been modeled by using a simplified stochastic approach. The influence of the curved diffusion edge on the electric field ill the periphery has been considered and electric field equations have been derived from the cylindri cal Poisson's equation. The electric field in the multiplication layer is s ignificantly reduced when a partial charge sheet is incorporated in the dev ice's periphery. The modeled 2D gain profile for such a device agrees with experiment and demonstrates an effective suppression of the premature edge breakdown. These results and the uniformity issue of the 2D gain profiles a re further discussed. From our analyses, we find that controlling the diffu sion process within the p(+) InP top layer and patterning the charge sheet mesa structure are most likely to affect the uniformity and symmetry of the 2D gain profiles for the InP/InGaAs SAGCM ASDs. (C) 2000 American Vacuum S ociety. [S0734-2101(00)04102-6].