Performance improvement of HfO2-based ferroelectric with 3D cylindrical capacitor stress optimization

• Published in: Journal of applied physics 2024-06, Vol.135 (23)
• Main Authors: Li, Wenqi, Xia, Zhiliang, Fan, Dongyu, Fang, Yuxuan, Huo, Zongliang
• Format: Article
• Language: English
• Subjects: Capacitors; Commercialization; Ferroelectric materials; Ferroelectricity; Hafnium oxide; Orientation; Phase ratio; Polarization; Stress distribution
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0205852

To meet commercialization requirements, the distributions of materials in hafnium-based ferroelectric devices—including their phase and orientation—need to be controlled. This article presents a method for improving the ferroelectric phase ratio and orientation by adjusting the stress distribution of the annealing structure in a three-dimensional capacitor. In such a structure, stress can be applied in three directions: tangential, axial, and radial; there are, thus, more ways to regulate stress in three-dimensional structures than in two-dimensional structures. This work sought to clarify the role of the stress direction on the proportions and orientations of ferroelectric phases. The results of stress simulations show that a structure with an internal TiN electrode, but no filling provides greater axial and tangential stresses in the hafnium-oxide layer. In comparison with the case of the hole being filled with tungsten, the proportion of the O phase is increased by approximately 20%, and in experiments, the projection of the polarization direction onto the normal was found to be increased by 5%. Axial and tangential stresses are regarded to be beneficial for the formation of the O phase and for improving the orientation of the polarization direction. This work provides a theoretical basis and guidance for the three-dimensional integration of hafnium-based ferroelectric materials.