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

In this letter, we report on nFinFETs degradation during stress exploiting ID and IG noise analysis. We employed a stress/measure approach to monitor device characteristics at different levels of cumulative stress. IG-VG and ID-VG indicators suggest defects generation to occur away from the channel. This is confirmed by the quantitative analysis of ID and IG 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 ID-t and IG-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, ID-t and IG-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, ID and IG RTN/instabilities might originate from mechanisms involving different entities.