Depolarization induced III–V triatomic layers with tristable polarization states

Ke, Changming; Hu, Yihao; Shi, Liyi

doi:10.1039/d3nh00026e

Cited by 1 publication

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, similar to what was experimentally observed in ferroelectric PVDF films, a thickness dependent depolarization field qualitatively fits very well to the drop of E c below 10 nm film thickness in Al 1−x Sc x N. [31] Very recently, it has also been demonstrated by first-principles calculations that reducing the thickness of usually non-switchable Wurtzite III-V semiconductors (e.g., AlSb) could result in polarization switching capability (i.e., ferroelectricity), due to the depolarization field which scales with ∝1/d. [32] The decrease in E c in our work is also reflected in the increase in 𝜖 r below 10 nm film thickness, as illustrated in Figure 4a. In addition, 𝜖 r increases to even higher values after cycling, which is especially pronounced for the thinner films (Figure 4b).…”

Section: Coercive Field Scaling In Ultrathin Al 074 Sc 026 Nsupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

In‐Grain Ferroelectric Switching in Sub‐5 nm Thin Al_0.74Sc_0.26N Films at 1 V

et al. 2023

View full text Add to dashboard Cite

Analog switching in ferroelectric devices promises neuromorphic computing with the highest energy efficiency if limited device scalability can be overcome. To contribute to a solution, one reports on the ferroelectric switching characteristics of sub‐5 nm thin Al0.74Sc0.26N films grown on Pt/Ti/SiO2/Si and epitaxial Pt/GaN/sapphire templates by sputter‐deposition. In this context, the study focuses on the following major achievements compared to previously available wurtzite‐type ferroelectrics: 1) Record low switching voltages down to 1 V are achieved, which is in a range that can be supplied by standard on‐chip voltage sources. 2) Compared to the previously investigated deposition of ultrathin Al1−xScxN films on epitaxial templates, a significantly larger coercive field (Ec) to breakdown field ratio is observed for Al0.74Sc0.26N films grown on silicon substrates, the technologically most relevant substrate‐type. 3) The formation of true ferroelectric domains in wurtzite‐type materials is for the first time demonstrated on the atomic scale by scanning transmission electron microscopy (STEM) investigations of a sub‐5 nm thin partially switched film. The direct observation of inversion domain boundaries (IDB) within single nm‐sized grains supports the theory of a gradual domain‐wall driven switching process in wurtzite‐type ferroelectrics. Ultimately, this should enable the analog switching necessary for mimicking neuromorphic concepts also in highly scaled devices.

show abstract

Section: Coercive Field Scaling In Ultrathin Al 074 Sc 026 Nsupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%