Fig. 1. (Color online) (a) Cross-sectional view of designed peaking Ge-on-Si PD. (b) I–V characteristics of designed peaking Ge-on-Si PD in dark illuminated state. (c) The simulated normalized S₂₁ response of vertical Ge-on-Si PD with small peaking, large peaking and without peaking. (d) The experimental and fitted result of normalized RF response of vertical Ge-on-Si PD with small inductance, the inset is the optical micrograph of peaking PD. (e–f) The experimental and fitted magnitude/phase part of the small signal S₁₁ reflection parameters from 100 MHz to 60 GHz at –3 V bias voltage, the blue and red line represent experimental and fitted result, respectively.

Fig. 2. (Color online) (a) Measured 70, 80, 90, and 100 Gbit/s NRZ eye diagrams under 3 V reverse-bias voltage. (b) Measured 40, 50, 60, and 64 Gbaud PAM-4 eye diagrams under 3 V reverse-bias voltage.