Bilayer-Barrier Ferroelectric-HfO2 Tunnel Junction with High ON Current and Giant ON/OFF ratio Arising from Resonant Tunneling

The hafnium oxide (HfO
2
) 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-HfO
2
. Compared with FE-HfO
2
/SiO
2
case, FE-HfO
2
/Ta
2
O
5
based FTJ shows high ON current (J
ON
) 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.