Enhanced polarization and endurance properties of ZrO-based ferroelectric capacitor using HfOinterfacial layer.

Recently discovered ferroelectricity in fluorite-structure ZrOthin film has attracted increasing and intense interest due to its lower crystallization temperature and higher content in nature in comparison to hafnium oxide. Here, the effect of HfOinterfacial layer on the ferroelectric properties of ZrOthin films is investigated systematically by designing four types of interfacial structures. It is revealed that the ferroelectric orthorhombic phase, remanent polarization, and endurance can be improved in ZrOthin film by inserting both a top- and bottom-HfOinterfacial layer. A maximal ferroelectric remanent polarization (2) of 53.4C cmand an optimal endurance performance of 3 × 10field cycles under frequency of 100 kHz are achieved in Pt/HfO/ZrO/HfO/Pt capacitors, with ferroelectric stacks being crystallized at 450 °C via post-deposition annealing method. X-ray photoelectron spectroscopy analysis confirms that the HfObottom-layer plays a very important role in the formation of a higher ratio o-phase, thus enhancing the ferroelectricity. These results suggest that designing appropriate interfaces would help achieve excellent ferroelectric properties in ZrOfilms.