Proton‐Radiation Hardening of High‐Speed Ge/Si Integrated Photodetectors for Space Applications

ABSTRACT High‐speed Ge/Si integrated photodetectors are essential for spaceborne photonic links, yet proton irradiation can strongly increase leakage current and noise, compromising long‐term reliability. Here, we performed a broad‐spectrum proton‐irradiation study on high‐speed Ge/Si integrated photodetectors and validated hydrogen loading as a radiation‐hardening approach. An RCF‐calibrated energy–fluence spectrum combined with Geant4 energy‐deposition simulations enabled dose‐calibrated testing at cumulative deposited doses of 158, 316, 790, and in the silicon layer under a laser–plasma‐driven broadband proton beam with a maximum energy of . For untreated devices, the bandwidth decreased from to at , whereas the dark current at a reverse bias increased from to its preirradiation level. Hydrogen‐loaded devices remained functional and exhibited improved tolerance, retaining bandwidth ( of the preirradiation reference) while limiting the dark‐current increase to at . This demonstrates a practical hardening route for space‐relevant integrated photodetectors.