Single-Event Transients in a Commercially Available, Integrated Germanium Photodiode for Silicon Photonic Systems

Ion-induced SETs were captured from a germanium photodiode (PD) in an integrated silicon photonics technology platform. Statistics from 400 ion-strike events were extracted for various optical powers and LETs incident on the PD. The results show that the transient peak decreases with increasing optical power. TCAD simulation results indicate that photo-generated carriers decrease the built-in electric field of the PD, thereby decreasing the transient peak. The photo-generated carriers also increase the probability of Auger recombination, which further reduces the transient peak under illuminated conditions, but this effect is small and does not contribute significantly to the transient peak reduction. Finally, a short case study with an ON–OFF keying modulation scheme is presented to show how these transients have the potential to corrupt bits in realistic communication systems. Furthermore, it is also shown that hardening techniques can be utilized to mitigate bit errors in communication systems that use integrated Ge PDs.