48 GHz High-Performance Ge-on-SOI Photodetector With Zero-Bias 40 Gbps Grown by Selective Epitaxial Growth

High-performance normal-incidence p-i-n Ge photodetectors for 1550 and 1310 nm were grown by selective epitaxial growth on SOI substrate with in situ thermal annealing and surface Si passivation. Bulk leakage current density and surface leakage density as low as 3.4 mA/cm
²
and 0.4 μA/cm are achieved under -1 V, respectively. Resonance optical responsivity at 1550 and 1310 nm are 0.27 and 0.59 A/W under zero-bias, respectively. A 3-dB bandwidth as high as 48 GHz is obtained at -3 V. Clear open eye diagrams at 40 Gbps are demonstrated under zero-bias at 1550 nm.