Molecular dynamics investigation of heteroepitaxial growth of quaternary AlInGaN on wurtzite-GaN surface along 0001 direction
A Debnath and CK Das, JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, 43, 012702 (2025).
DOI: 10.1116/6.0004113
We conducted molecular dynamics simulations of heteroepitaxial vapor
deposition of the AlInGaN film on the polar 0001 GaN surface to
investigate the influence of the substrate temperature and Al/In ratio
on the epitaxial film. Time- and position-dependent boundary constraints
were implemented to ensure appropriate growth conditions in the vapor
phase region, the near-surface solid, and the bulklike solid region of
the growing film. The simulation utilized an optimized Stillinger-Weber
potential to describe the interactions among Al-In-Ga-N atoms. For the
compositional study, the ratios of Al/In used are 1/9, 3/7, 1/1, 7/3,
and 9/1. To investigate the temperature effect on the substrate, four
different growth temperatures above half of the simulated melting
temperature of the GaN substrate were employed. Following the growth of
the AlInGaN film, surface roughness, domain structure, crystallinity,
and dislocations were analyzed. Our findings indicate that surface
roughness and crystallinity increase with higher Al/In ratios as well as
elevated substrate temperatures. The domain size was also observed to
increase with higher Al/In ratios and temperatures. At lower
temperatures and low Al/In ratios, islands of different polytypes emerge
with a high height-to-width ratio, resulting in a highly polytypic
structure. The annealing process following growth significantly improves
crystallinity and reduces surface roughness. From the dislocation study,
it was observed that the maximum number of dislocation lines is of type
1/3 1 1
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