Experimental study of endurance characteristics of Al-doped HfO2 ferroelectric capacitor.

In this work, the endurance characteristics of Al-doped HfO2 (HAO)-based metal-ferroelectric-metal (MFM) capacitors (which were annealed at 1,000 ℃) with various doping concentrations were investigated. The doping concentration was optimized for the high annealing temperature (1,000 ℃) process. To investigate the impact of cycling pulses on the endurance characteristics of HAO-based MFM capacitor, the rise/fall time (tr/f) and hold time (th) for the cycling pulses were varied. Moreover, by adopting the recoverable fatigue process, the endurance characteristics under repetitive wake-up/fatigue processes were studied. The HAO capacitors achieved the remnant polarization (2Pr) of 23.767 µC/cm2 at pristine state under the high annealing temperature. Furthermore, it was demonstrated that the endurance characteristics (~108 cycles) of the HAO capacitors were comparable to them of other HfO2-based ferroelectric capacitors. Lastly but not least, it turned out that the amount of oxygen and oxygen vacancies in the HAO thin film was dependent of doping concentrations for the film. The impact of oxygen and oxygen vacancies was quantitatively analyzed, in detail, with TEM, XPS, and GIXRD analysis.