Top Electrode Engineering for High‐Performance Ferroelectric Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> Capacitors
Beom Yong Kim, In Soo Lee, Hyeon Woo Park, Yong Bin Lee, Suk Hyun Lee, Minsik Oh, Seung Kyu Ryoo, Seung Ryong Byun, Kyung Do Kim, Jae Hoon Lee, Deok‐Yong Cho, Min Hyuk Park, Cheol Seong Hwang
Abstract
Abstract This work systematically studies the TiN, Ru, and RuO 2 top electrodes (TEs) effects on the ferroelectric properties of Hf 0.5 Zr 0.5 O 2 (HZO) films. The Ru top electrode significantly improves the ferroelectric performance even with the conventional TiN bottom electrode. The high two‐remanent polarization (2 P r ) value (≈65 µC cm −2 ) is obtained with the capacitor with Ru TE, which is ≈1.5 times higher than that of the capacitors with the TiN and RuO 2 TEs. Moreover, it does not break down to 1 × 10 9 cycling with a high cycling electric field of 4.0 MV cm −1 , while others do lower cycle numbers. Further enhancement can be achieved by inserting a 2‐nm‐thick HfON interfacial layer between the HZO film and TiN bottom electrode while keeping the Ru/HZO top interface structure. The capacitor does not break down even at an electric field strength of 4.8 MV cm −1 , at which a 2 P r value of ≈67 µC cm −2 is achieved. Furthermore, it can endure 1 × 10 11 switching cycles while a 2 P r value of 45–53 µC cm −2 is retained. Therefore, this study elucidates that interfacial engineering is an important technology that can overcome the trade‐off relationship between P r and endurance, a critical issue in ferroelectric doped HfO 2 ‐based films.