Study of bistable defects created after high-temperature annealing in 34 MeV proton irradiated Si diodes

The behaviour of leakage current and depletion voltage have been studied on silicon diodes of different resistivity during the full annealing period after 34 MeV proton irradiation. After the irradiation the measurements were performed after heating the samples to cover the complete annealing curve. The hardness factor was estimated through the measurement of the diode leakage current as a function of annealing time. The diode leakage current and depletion voltage values show a significant decrease as a function of time after heating at high temperatures. This effect is typical of bistable defects. The defect can be activated by illumination, forward bias and further heating. The average time constant of the de-activation process has been found to be 4 h, independently of the activation process.