A New Planar InGaAs–InAlAs Avalanche Photodiode

We discuss a new simple InGaAs-InAlAs avalanche photodiode (APD) with a planar buried multiplication region. Some of the advantages compared to standard APDs are as follows: 1) The thickness of the avalanche and the charge control regions are accurately controlled by molecular beam epitaxy growth in contrast to the standard diffusion process; 2) InAlAs is the multiplication material (avalanching faster electrons) instead of InP (avalanching slower holes); 3) InAlAs avalanche gain has a lower noise figure than that for InP; 4) a guard ring is not required; 5) fabrication is as simple as that for a p-i-n detector; 6) The APD has high wafer uniformity, and high reproducibility; 7) The InAlAs breakdown voltage is lower than InP, and its variation with temperature is three times lower than that for InP; 8) Excellent aging and reliability including Telcordia GR-468 qualification for die and modules; 9) High gain-bandwidth product as high as 150 GHz; and 10) high long-range (LR-2) bit-error-rate 10 -12 receiver sensitivity of -29.0 dBm at 10 Gb/s, -28.1 at 10.7Gb/s, and -27.1 dBm at 12.5 Gb/s