Interface engineering of BEOL compatible ferroelectric Y:HfO2 device for enhanced endurance

A novel BEOL compatible three-layered structure based on ferroelectric (FE) HfO
2
device is proposed for endurance improvement. This structure consists of an ultrathin Y
2
O
3
passivation layer, a FE Y-doped HfO
2
layer (YHO, deposited at room temperature (RT)) and a buffer CeOx layer. Y
2
O
3
is used for passivation of defects with the bottom electrode (NiSi
2
) while CeOx is used to control oxygen vacancies in FE-YHO. Good FE hysteresis is observed in YHO (from 12.5 to 9.2 nm) while low temperature activation annealing (200°C-400°C after CeOx deposition), greatly enhances the FE-YHO properties. After annealing at 350□, this novel capacitor (YHO= 9.2nm) shows lower leakage current, initial remanent polarization of 25μC/cm
²
(2Pr), excellent endurance up to 1e12 cycles at low power operation conditions and good data retention at RT.