Self-structuring in Zr_1-xAl_xN films as a function of composition and growth temperature

Area of Science:

• Materials Science
• Thin Film Deposition
• Crystallography

Background:

• Zirconium Aluminum Nitride (ZrAlN) films are technologically relevant materials.
• Understanding nanostructure formation is crucial for optimizing material properties.
• Surface diffusion and segregation play key roles in film growth.

Purpose of the Study:

• Investigate nanostructure formation in Zr_1-xAl_xN films.
• Explore the influence of composition and growth conditions on phase segregation.
• Determine the relationship between crystal structure and decomposition behavior.

Main Methods:

• High-mobility growth conditions for Zr_1-xAl_xN film deposition.
• Analysis of nanostructure formation via surface-diffusion-mediated segregation.
• First-principles calculations to support experimental findings.

Main Results:

• Formation of a hard nanolabyrinthine lamellar structure in Zr_1-xAl_xN (0.2 ≤ x ≤ 0.4) with c-ZrN and w-AlN domains.
• Development of a nanocomposite wurtzite lattice with Al-rich ZrN domains for high AlN content (x > 0.49).
• Observed slow diffusion in wurtzite films, indicating crystal structure-dependent decomposition.

Conclusions:

• Nanostructure in ZrAlN films is governed by immiscibility, interfacial, surface, and strain energy.
• Atom mobility and crystal structure significantly influence the resulting nanostructure and decomposition.
• Iso-structural decomposition is unlikely in c-Zr_1-xAl_xN, while w-Zr_1-xAl_xN is stable for high AlN content.