Quantitative Analysis on the Interaction Between Channel Carrier and Remote Trap in HfxZr1-xO2/SiO2 Interface in Ferroelectric Field-Effect-Transistor

초록

In this work, the polarization-dependent operating characteristics of TiN/HfxZr1-xO2(HZO)/SiO2/Si ferroelectric FETs (FeFETs) are investigated, and remote HZO/SiO2 interface traps (Dit,FE/DE) are quantitatively separated from Si/SiO2 interface traps (Dit0). X-ray photoelectron spectroscopy (XPS) reveals an oxygen-vacancy (VO)-rich HfSiOx layer at the HZO/SiO2 interface. Based on the transistor operation theory and trap/polarization-switching charge distribution, the difference in the W1 and W0 states is determined by whether the HZO/SiO2 interface traps are filled and emptied, respectively. Subthreshold current method (SCM) shows that SS increases from ∼95 mV/dec (W1 state) to 110 mV/dec (W0 state), yielding effective interface trap density (Dit,eff) values of 4 × 1012 and 7.8 × 1012 cm−2eV−1, respectively; their difference (3.8 × 1012 cm−2eV−1) corresponds to Dit,FE/DE. Methods that exploit the frequency-dependent response of the defect states–Multi-frequency C-V (MFCV) and Terman method (TM)–yield Dit0 and Dit,FE/DE values that match the SCM results. Accounting for the capacitive-projection factor of 2.5, the actual HZO/SiO2 interface trap density (DFE/DE) is ∼1 × 1013 cm−2eV−1, approximately 2.5 times higher than Dit0. The combined SCM-MFCV-TM framework thus furnishes a rapid, purely electrical metric for monitoring HZO/SiO2 quality and guides strategies to suppress remote trap-carrier interaction (RTCI)-driven degradation in FeFET performance.

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