Performance Recovery of Silicon-Avalanche- Photodiode Electron Detector by Low-Temperature Annealing

We report that the silicon avalanche photodiode (APD) for electron detection almost fully recovers from the damage caused by electron irradiation by annealing. With the electron irradiation at an energy of 8 keV, a prominent increase of the non-amplified component of the dark current was observed, and the gain and energy resolution for APD were significantly lowered. Upon annealing at 500 K for 10 h, the dark current was reduced and the gain and energy resolution were recovered. We also show that the dark current of APD depends on the material of the surface protection layer. The origin of the degradation and recovery is discussed.