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.