Low-voltage operation and high endurance of 5-nm ferroelectric Hf0.5Zr0.5O2 capacitors

In this letter, the ferroelectric (FE) properties of 5-nm-thick Hf0.5Zr0.5O2 (HZO) films deposited by atomic layer deposition have been investigated. By reducing the HZO film thickness to 5 nm, low-voltage operation (1.0 V) of the HZO-based capacitor was achieved while maintaining a remnant polarization (P-r) of about 10 mu C/cm(2) (i.e., 2P(r) of 20 mu C/cm(2)). Meanwhile, in order to form an orthorhombic phase, which is responsible for FE properties, a rapid thermal annealing process was performed after TiN top electrode deposition. The FE properties were realized after low temperature annealing (450 degrees C for 1 min), making them compatible with the back-end of the line. In addition, the low operating voltage and the suppression of an additional monoclinic phase formation by stress-induced crystallization induced a robust endurance (>10(10) cycles at 1.2 V) of the 5-nm-thick HZO sample. Published by AIP Publishing.