Influence of Annealing Temperature on the Structural and Electrical Properties of Si-Doped Ferroelectric Hafnium Oxide

Abstract

The ferroelectric properties of hafnium oxide films are strongly influenced by the crystallization process due to the interaction of thermodynamics, kinetics, and mechanical stress. In this work, the influence of annealing temperature on the crystallographic properties and microstructure of Si-doped hafnium oxide thin films as well as their ferroelectric properties are investigated by X-ray diffraction, transmission Kikuchi diffraction, and electrical characterization. The findings reveal the emergence of a [100] and [110] out-of-plane texture for metal−ferroelectric− metal (MFM) and metal−ferroelectric−insulator−semiconductor (MFIS) capacitor structures with increasing annealing temperature, respectively. In combination with observed stress relaxation at higher temperatures and the evolution of the wake-up behavior, insights into the crystallization process and the influence of the interplay of microstructure and stress on the ferroelectric properties of hafnium oxide thin films are given.

Substrate-dependent differences in ferroelectric behavior and phase diagram of Si-doped hafnium oxide

“…That stress relaxation is linked to the out-of-plane orientation and increased ferroelectric behavior has been reported previously [23,39]. Moreover, previous results provide strong evidence by X-ray diffraction, that lower stress levels are present for thicker interfaces [39]. The increase in interface thickness is most likely the driving factor for increased ferroelectric behavior with increasing annealing temperature as well, besides the changes in crystallographic texture [37,38].…”

“…This suggest a reduction of ferroelastic switching for thicker interfaces and therefore a reduction in tensile in-plane stress of the HSO film [38]. That stress relaxation is linked to the out-of-plane orientation and increased ferroelectric behavior has been reported previously [23,39]. Moreover, previous results provide strong evidence by X-ray diffraction, that lower stress levels are present for thicker interfaces [39].…”

Fluorite‐Structured Ferroelectric and Antiferroelectric Materials: A Gateway of Miniaturized Electronic Devices

“…Consequently, the initial polarization versus voltage curve is not strongly pinched. [ 56 ] The largest remanent polarization is measured for annealing temperatures ranging between 800 and 900 °C. For this reason, HSO is not suited for BEoL applications, where high requirements are applied with regard to the maximum temperature budget, but interesting for the use in the FEoL, where high temperatures are normally present.…”

“…[6] Compared to HZO, HSO crystallizes at significantly higher temperatures, starting at around 550-600 °C. [56] In addition, the annealing temperature influences the crystallographic orientation. In the case of MFM structures, lower annealing temperatures (i.e., 600 °C) result in a strong in-plane orientation of the polarization axis resulting in a strong AFE-like (i.e., pinched) hysteresis loop in the pristine state.…”

Effect of Al2O3 interlayers on the microstructure and electrical response of ferroelectric doped HfO2 thin films

“…Crystallographic analysis via transmission Kikuchi diffraction (TKD) Keller R. R. and Geiss (2012); Lederer et al (2019) of hafnium oxide films have revealed the presence of strong crystallographic textures in the film Lederer et al (2019,2020). Under certain conditions, even semi-epitaxial growth was observed in polycrystalline layers Lombardo et al (2021); Lederer et al (2021b). It is therefore pivotal to consider crystallographic textures in the ferroelectric layer as well.…”