Monitoring Stress-Induced Defects in HK/MG FinFETs Using Random Telegraph Noise

In this letter, we report on nFinFETs degradation during stress exploiting I_D and I_G noise analysis. We employed a stress/measure approach to monitor device characteristics at different levels of cumulative stress. I_G-V_G and I_D-V_G indicators suggest defects generation to occur away from the channel. This is confirmed by the quantitative analysis of I_D and I_G stationary RTN signals at operating conditions, which show no correlation as opposite to what reported for planar FETs. Moreover, we analyze for the first time the I_D-t and I_G-t non-stationary instabilities during stress. The results confirm that the generation of defects responsible for SILC occurs away from the channel. Only in highly stressed devices, I_D-t and I_G-t curves observed during stress exhibit anti-correlation, due to comparable values of the gate and drain current levels originated by the high defect density. Hence, in nFinFETs, I_D and I_G RTN/instabilities might originate from mechanisms involving different entities.