Analysis of transient charging components in NBTI degradation studied for TaN gated HfO2/SiO2 dielectrics

Threshold voltage (V,h) shift under the NBT-stress of TaN gated HfO₂/SiO₂ stacked gate dielectrics has been studied by conventional DC and the pulsed measurements. A large Vth shift in the early stage of stress occurs typically within 1 s by the fast transient charging under the stress as well as during the V_th measurement. Contributions of both charging components strongly depend on the film quality and also on the stress conditions. Therefore, an accurate deconvolution of measured DeltaV_th into each component is indispensable for accurate lifetime prediction and the understandings of the NBTI reliability.