Response of Waveguide-Integrated Germanium-on-Silicon p-i-n Photodiodes to Neutron Displacement Damage

摘要： The effects of 14-MeV neutron displacement damage (DD) on waveguide-integrated germanium-on-silicon p-i-n photodiodes (PDs) for silicon photonics have been investigated up to fluences of 7.5×1012 n/cm2 (14 MeV), or 1.4×1013 n1-MeVeq /cm2(Si). The study includes measurements of dark current-voltage characteristics across temperature from 150-375 K, measurements of PD junction capacitance, spectral response measurements from 1260 nm to 1360 nm, and frequency response measurements. The devices are found to be susceptible to DD-induced carrier removal effects; however, they also continue to operate without meaningful impact to performance for the DD dose levels examined. Since the PD test chips include silicon photonic integrated grating couplers and waveguides which carry the optical signal to the PD, some assessment of the impact of DD on these passive devices can also be inferred. This work does not examine the short-term annealing or transient behavior of the DD, and instead has only considered the lasting damage that remains after any initial period of room temperature annealing.