The preparation of gallium nitride
(GaN) film materials
has significant
importance in the semiconductor and thermoelectric sectors, serving
as essential core materials for chips, power supply, and communication
applications. The production of GaN thin films with reduced defect
density has emerged as a significant and continuous subject of research.
This work investigated the deposition process of GaN thin films on
an aluminum nitride nanopattern substrate via molecular dynamics simulation.
A comparison was made between the deposition process on the nanopatterned
and unpatterned substrates. Additionally, the impact of the substrate
temperature and nanopillar radius on the quality of the thin film
was examined. Results demonstrate that the use of a nanopillar pattern
on the substrate facilitates the acquisition of the deposited film
with a larger number of wurtzite structures and a reduced presence
of dislocations. In contrast to the persistent and extensive dislocations
formed in the thin films on an unpatterned substrate, the dislocations
present in the thin films on a patterned substrate exhibit shorter
lengths and more complexity. By appropriately elevating the temperature
of the substrate, it is possible to effectively decrease the complexity
of the atomic structure and enhance the thin film density. The correlation
between the stress and the temperature of the thin film deposited
on the patterned substrate is weak. The deformation of nanopillars
with a too small radius can cause the deposited atoms to move into
the nanovoid, aggravating the irregularity of the thin film surface
and the volume of defects. Moreover, the excessive size of the nanopillar
at which the surface area of the substrate approaches that of an unpatterned
substrate can increase the occurrence of dislocations in the deposited
film. This observation implies that the nanovoid ratio inside the
nanopillar has a substantial impact on the deposition quality of the
thin film. This study focuses on the deposition of GaN films on substrates
with nanopatterns at the nanoscale, assesses the impact of nanopatterning
degree on the growth quality of film, and acquires data on the temperature
range and structural characteristics of high-quality films exhibiting
high density and few dislocations.
