Top Electrode Engineering for High‐Performance Ferroelectric Hf0.5Zr0.5O2 Capacitors

• Published in: Advanced materials technologies 2023-08, Vol.8 (16), p.n/a
• Main Authors: Kim, Beom Yong, Lee, In Soo, Park, Hyeon Woo, Lee, Yong Bin, Lee, Suk Hyun, Oh, Minsik, Ryoo, Seung Kyu, Byun, Seung Ryong, Kim, Kyung Do, Lee, Jae Hoon, Cho, Deok‐Yong, Park, Min Hyuk, Hwang, Cheol Seong
• Format: Article
• Language: English
• Subjects: ferroelectric Hf0.5Zr0.5O2 capacitors; HfON interface layers; Interface engineering; Ru top electrodes; RuO2 top electrodes; TiN top electrodes
• ISSN: 2365-709X; 2365-709X
• DOI: 10.1002/admt.202300146

This work systematically studies the TiN, Ru, and RuO2 top electrodes (TEs) effects on the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) films. The Ru top electrode significantly improves the ferroelectric performance even with the conventional TiN bottom electrode. The high two‐remanent polarization (2Pr) 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 RuO2 TEs. Moreover, it does not break down to 1 × 109 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 2Pr value of ≈67 µC cm−2 is achieved. Furthermore, it can endure 1 × 1011 switching cycles while a 2Pr 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 Pr and endurance, a critical issue in ferroelectric doped HfO2‐based films. This work systematically studies the TiN, Ru, and RuO2 top electrodes' effects on the ferroelectric properties of Hf0.5Zr0.5O2 films. The Ru top electrode significantly improves the ferroelectric performance even with the conventional TiN bottom electrode obtaining high two‐remanent polarization (2Pr) value (≈65 µC cm−2) and enduring 1 × 1011 switching cycles with HfON interfacial layer.