Edge Breakdown Suppression in Avalanche Photodiodes Using an Attached Step Guard Ring

This study aims to investigate the effectiveness of different guard ring (GR) structures in suppressing edge breakdown issues in InGaAs/InP planar avalanche photodiodes (APDs) with a thicker multiplication layer design through highly realistic simulations. Based on the simulation results of the limitations of conventional GR structures, we introduce a novel concept known as attached step GRs (ASGR). Through this feasible diffusion structure, edge breakdown has been improved, with a 23% increase in breakdown voltage compared to traditional structures. The higher electric field is effectively confined within the central region of the multiplication region, while also achieving a threefold increase in current gain and quantum efficiency (QE) enhancement of over 20%.