Investigation on High-Temperature and High-Field Reliability of NMOS Devices Fabricated Using 28 nm Technology After Heavy-Ion Irradiation

This paper investigates the degradation of 28 nm technology NMOS devices under high-temperature and high-field conditions following heavy-ion irradiation. The effects of stress time, stress magnitude, temperature, device structural dimensions, and heavy-ion radiation fluence on device degradation were analyzed. The results indicate that under positive gate bias stress, the threshold voltage of NMOS devices exhibits a continuous positive shift. Increased stress time, higher stress magnitude, elevated temperature, and reduced device structural dimensions all aggravate device degradation. The combined effects of electrical stress and radiation lead to a degradation that initially decreases and then increases. This is because the trap charges generated in the gate oxide layer by radiation are positive charges at low fluence, compensating for the negative charges generated under electrical stress, thereby reducing degradation. However, at high fluence, the negative interface trap charges increase, while radiation also generates positive charges in the shallow trench isolation (STI) region. These two factors collectively contribute to increased device degradation.