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

This paper reports the planar-structure InAlGaAs-InAlAs superlattice avalan che photodiodes (SL-APDs) with a Ti-implanted guard-ring, which were develo ped for a compact and high-sensitivity 10-Gb/s optical receiver application . The-design and fabrication of the novel concept planar-structure includin g the Ti-implanted guard-ring are described. The characteristics of the pla nar APDs are 0.36 muA dark current at a multiplication factor of 10, 67% qu antum efficiency, 110-GHz gain-bandwidth (GB)product, 15-GHz top-bandwidth, and -27.2-dBm sensitivity at 10 Gb/s, The reliability was preliminary test ed and the lifetime of longer than 10(7) h at 50 degreesC was estimated. Th e dark current characteristics including temperature dependence and the exc ess noise characteristics are also analyzed. All the obtained characteristi cs exhibit the practical availability of the planar SL-APDs in the 10-Gb/s trunk line optical receiver uses.