Abstract Scope |
Hafnia has several allotropy phases, such as monoclinic (the most thermodynamically stable phase at room temperature and 1 atm), tetragonal, cubic and orthorhombic. Recently, ferroelectric characteristics was discovered in doped hafnia thin films with meta-stable orthorhombic phase (space group: Pca21). Because of CMOS process compatibility of hafnia, doped Hf oxide thin films have been extensively investigated for ferroelectric device applications. Particularly, atomic layer deposited Hf-Zr oxide thin films shows excellent ferroelectricity and scalability at relatively low temperature (<400C). In this presentation, effects of oxidizing agents, Hf/Zr compositions and doping elements of thermal ALD will be discussed in terms of materials and electrical characteristics. Particularly, we will discuss strategies to lower the phase transition thermal budget while maintaining (or even enhancing) ferroelectric properties and reliability. |