Design and Fabrication of High-Breakdown InGaAs APDs with MOCVD Zn-Diffused Guard Rings

초록

A diffusion-geometry engineering approach based on recessed metal-organic chemical vapor deposition (MOCVD) Zn diffusion is demonstrated for suppressing premature edge breakdown in InGaAs/InP separate absorption, grading, charge, and multiplication avalanche photodiodes (SAGCM APDs). TCAD simulations show that a gradual diffusion geometry improves electric-field uniformity and suppresses field crowding at the multiplication-region edge. The proposed diffusion geometry was implemented using recessed MOCVD Zn diffusion and examined by cross-sectional SEM. Compared with a conventional solid-phase Zn-diffused APD, the proposed device exhibits a 100× reduction in dark current, a 7.2-V increase in punch-through and breakdown voltages, and a multiplication gain enhancement from 13 to 138. These results demonstrate that diffusion-geometry engineering provides an effective route toward high-gain, low-leakage InGaAs/InP APDs. © 1980-2012 IEEE.

키워드