A High-Speed and Low-Breakdown-Voltage Silicon Avalanche Photodetector

A silicon avalanche photodetector with a low breakdown voltage of -6.78 V is demonstrated by narrowing down the intrinsic layer width of interdigitated p-i-n junctions to ~ 150 nm. It reaches the physical limit of avalanche breakdown in which the performance degradation caused by the Zener tunneling process is negligible. Dark current at -4 V is measured, and a responsivity (gain) exceeding 1.424 A/W (110) at -6.75 V is obtained with an 850-nm laser illumination. The intrinsic bandwidth is determined to be 10 GHz, suggesting our device is applicable for a 10-Gb/s high-speed optical receiver application and beyond.