Direct Evidence of Oxygen Vacancy Generation in Whole Gate Stacks Through Multiple Electrical and Atomic-Scale Physical Methods as the Cause of Endurance Failure in FeFETs

We have experimentally confirmed that the oxygen vacancy (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{O}}$</tex>) generation within whole gate stacks is the origin of the endurance failure in Si FeFET by multiple electrical methods and atomic-scale physical characterization techniques. Through gate leakage, lowfrequency noise, and split I-V measurements, we found that defect generation occurs in whole gate stacks and electron-hole recombination during bipolar cycling plays a dominant role. Furthermore, we determined that the type of the generated defects is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\mathrm{O}}$</tex> based on scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) characterizations.