High-speed, high-reliability planar-structure superlattice avalanche photodiodes for 10-Gb/s optical receivers

This paper reports the planar-structure InAl-GaAs-InAlAs superlattice avalanche photodiodes (SL-APDs) with a Ti-implanted guard-ring, which were developed for a compact and high-sensitivity 10-Gb/s optical receiver application. The design and fabrication of the novel concept planar-structure including the Ti-implanted guard-ring are described. The characteristics of the planar APDs are 0.36 /spl mu/A dark current at a multiplication factor of 10, 67% quantum efficiency, 110-GHz gain-bandwidth (GB) product, 15-GHz top-bandwidth, and - 27.2-dBm sensitivity at 10 Gb/s. The reliability was preliminary tested and the lifetime of longer than 10/sup 7/ h at 50/spl deg/C was estimated. The dark current characteristics including its temperature dependence and the excess noise characteristics are also analyzed. All the obtained characteristics exhibit the practical availability of the planar SL-APDs in the 10-Gb/s trunk line optical receiver uses.