No abstract

The degradation of NMOSFETs due to hot-carrier effects under DC and RF stress was studied experimentally. The experimental results indicate that DC stress leads to more serious performance degradation than RF stress. It has also been found that channel length and width can change the worst DC stress condition. Moreover, RF performance degradation can be explained by DC performance degradation. A new model is proposed to predict the degradation characteristics of devices under RF stress by the degradation under DC stress. By using knowledge-based neural network (KBNN), the model shows good accuracy. It can also reduce test data set and simplify testing process.

In this paper, the degradation of low-frequency (LF) noise under different RF stress conditions in nMOSFETs has been reported and compared with the conventional DC stress condition. LF noise increases after RF stress and the increment of noise under RF stress at a large V gs value is bigger than that caused by DC stress. The change in LF noise intensity under RF stress raised more rapidly at large V gs values than that at small V gs values, which are contradictory to LF noise performance after DC stress. The influence of the input power and frequency of stress on LF noise has also been investigated separately. As the stress input power or frequency increases, the increment of noise intensity rises as well. The γ decreases as the growth of the stress input power or frequency, and the values of γ are below 1 after 18 GHz RF stress. The results provide experimental verification that the interface traps generated by RF stress play a major role in the degradation of LF noise.