Can Interface Layer be Really Free for Hf_xZr_1-xO₂ Based Ferroelectric Field-Effect Transistors With Oxide Semiconductor Channel?

The HfxZr1-xO2 (HZO) based ferroelectric field-effect transistors (FeFETs) with oxide semiconductor channel have been proposed to have the potential of interface layer (IL) free, but the FeFET properties with real IL-free structure has rarely been demonstrated. In this work, we experimentally and theoretically clarified that real IL-free FeFET with ferroelectric (FE) HZO as gate oxide is difficult to get memory window (MW) because the polarization switching is difficult to occur due to insufficient positive charge compensation from oxide channel. In addition, we demonstrate that IL-free FeFETs with antiferroelectric (AFE) HZO provides a solution to get MW through positive subloop which does not require positive charge compensation in polarization changing. And an endurance performance up to 10(9) cycles is achieved in this FeFET structure. Our results provide new insights into engineering of HZO-based FeFET with oxide channel.