Ni doping significantly improves dielectric properties of La2O3 films

• Published in: Journal of alloys and compounds 2020-05, Vol.822, p.153469, Article 153469
• Main Authors: Li, Shuan, Lin, Youyu, wu, Yong, Wu, Yanqing, Li, Xingguo, Tian, Wenhuai
• Format: Article
• Language: English
• Subjects: Annealing; Dielectric properties; Doping; Electrical properties; Hafnium oxide; High k dielectric; Integrated circuits; Lanthanum; Lanthanum oxides; Leakage current; Nickel; Offsets; Oxides; Performance enhancement; Rare earth; Silicon; Sputtering
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.153469

With rapid development of integrated circuits, a long-standing challenge is to seek new gate dielectrics to replace HfO2. Lanthanum oxide (La2O3) has earned more and more attention with its attractive performance. Rational doping is an extremely effective way to further improve its dielectric properties. In this work, Ni is first doped into La2O3 by reactive co-sputtering for a novel dielectric film. We demonstrate that proper amount of Ni (∼10.04%) doping can effectively improve the performance of La2O3, exhibiting desired microstructure, large band gap (5.7 eV), suitable band offsets (VB = 2.15 eV, CB = 2.43 eV) and excellent electrical properties (k = 22.08). Furthermore, we optimized the performance of Ni-doped La2O3 (LNO) films by altering annealing temperature. The results suggest that 600 °C is the most suitable annealing temperature for LNO films, leading to a lower leakage current density of 2.06 × 10−4 A/cm2. Our work provides a new insight to select the suitable element to modify rare earth oxides for next-generation gate dielectrics. •Ni was first incorporated into La2O3 for a novel gate dielectric.•La2O3 films with different Ni doping amount are prepared by reactive sputtering.•Proper amount Ni doping can improve the dielectric properties of La2O3.•10.04% Ni-doped La2O3 films show best dielectric performance.•600 °C is optimal annealing temperature for Ni-doped La2O3 films.