Effects of thin SiN interface layer on transient I-V characteristics and stress induced degradation of high-k dielectrics

In this work, we present the effects of a SiN interface on charge trapping and de-trapping characteristics and time-dependent threshold voltage instability. The use of SiN interface structure was found to reduce the degradation in D_it and G_m even though it yielded higher bulk charge trapping. The higher bulk trap was evidenced from larger after-stress V_th degradation. Thus, it is believed that mobility degradation in HfO₂ is primarily caused by the degraded quality of the interfacial layer.