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

Abstract

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 (D it,FE/DE) are quantitatively separated from Si/SiO2 interface traps (D it0). X-ray photoelectron spectroscopy (XPS) reveals an oxygen-vacancy (V O)-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 similar to 95 mV/dec (W1 state) to 110 mV/dec (W0 state), yielding effective interface trap density (D it,eff) values of 4 x 1012 and 7.8 x 1012 cm-2eV-1, respectively; their difference (3.8 x 1012 cm-2eV-1) corresponds to D it,FE/DE. Methods that exploit the frequency-dependent response of the defect states-Multi-frequency C-V (MFCV) and Terman method (TM)-yield D it0 and D it,FE/DE values that match the SCM results. Accounting for the capacitive-projection factor of 2.5, the actual HZO/SiO2 interface trap density (D FE/DE) is similar to 1 x 1013 cm-2eV-1, approximately 2.5 times higher than D it0. 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.