Total ionizing dose effects in pinned photodiode complementary metal-oxide-semiconductor transistor active pixel sensor

A pinned photodiode complementary metal-oxide-semiconductor transistor (CMOS) active pixel sensor is exposed to ⁶⁰Co to evaluate the performance for space applications. The sample is irradiated with a dose rate of 50 rad (SiO₂)/s and a total dose of 100 krad (SiO₂), and the photodiode is kept unbiased. The degradation of dark current, full well capacity, and quantum efficiency induced by the total ionizing dose damage effect are investigated. It is found that the dark current increases mainly from the shallow trench isolation (STI) surrounding the pinned photodiode. Further results suggests that the decreasing of full well capacity due to the increase in the density, is induced by the total ionizing dose (TID) effect, of the trap interface, which also leads to the degradation of quantum efficiency at shorter wavelengths.