Growth kinetics in a strained crystal film on a wavy patterned substrate

Area of Science:

• Materials Science
• Surface Physics
• Continuum Mechanics

Background:

• Thin films can exhibit morphological instabilities, such as the Asaro-Tiller-Grinfeld instability.
• Patterned substrates can influence thin film morphology through surface interactions.
• Understanding these interactions is crucial for designing advanced materials and devices.

Purpose of the Study:

• To investigate the combined effects of Asaro-Tiller-Grinfeld instability and patterned substrates on strained thin film morphology.
• To develop a continuum model that incorporates elasticity, surface energy, and wetting interactions.
• To analyze the kinetic phase diagram governing film surface evolution.

Main Methods:

• Continuum surface diffusion model.
• Inclusion of elasticity, surface energy, and wetting interactions.
• Linear stability analysis of mechanical equilibrium and growth dynamics during annealing.

Main Results:

• The kinetic phase diagram was characterized as a function of time, film thickness, and wavelength ratios.
• The film surface can transition from an in-phase configuration to out-of-phase or non-ordered states.
• These transitions depend on the substrate pattern wavelength and annealing duration.

Conclusions:

• Substrate patterns can effectively control strained film morphology.
• The interplay between intrinsic film instability and substrate organization dictates the final film structure.
• This study provides insights into the rational design of patterned thin films with desired properties.