The　hafnium　oxide　(HfO2)　based　ferroelectric　tunnel　junction　(FTJ)　using　ferroelectric-dielectric　(FE-DE)　bilayer-barrier　structure　is　studied　by　physical　modeling.　The　FTJ　performance　strongly　depends　on　the　barrier　height　of　DE　with　respect　to　that　of　FE-HfO2.　Compared　with　FE-HfO2/SiO2　case,　FE-HfO2/Ta2O5　based　FTJ　shows　high　ON　current　(JON)　and　giant　ON/OFF　ratio.　The　underlying　physics　is　to　introduce　resonant　tunneling　(RT)　by　forming　a　quantum　well　and　to　shift　resonance　peak　close　to　the　Fermi　level.　The　switching　between　the　direct　tunneling　(DT)　and　RT　under　different　polarization　direction　leads　to　an　enhanced　TER　effect.　©　2023　The　Japan　Society　of　Applied　Physics.