High-frequency performance of separate absorption grading, charge, and multiplication InP/InGaAs avalanche photodiodes

Abstract

Planar separate absorption, grading, charge, and multiplication avalanche photodiodes that were fabricated on whole wafers are discussed. The high-frequency performance was investigated over a range of integrated charge (2.4-3.4*10/sup 12/ cm/sup -2/) and high field InP thickness (0.2-0.4 mu m). The bandwidth vs. gain dependence, gain-bandwidth product, minimum gain for useful bandwidth, and breakdown voltage are strongly correlated with the integrated charge and weakly correlated with the high field InP thickness. A very high gain-bandwidth product of 122 GHz was found. These observations are explained theoretically by considering ionization in the InGaAs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>