Novel Growth Pattern for Improving the Growth Quality of GaN Films during Deposition on a Nanocosine-Patterned Substrate by Molecular Dynamics Simulation

Improving the growth quality of thin films during deposition has been the subject of classical studies in semiconductor materials science. Previous research has shown that gallium nitride (GaN) films deposited on concave-patterned substrates exhibit better photoelectric properties. Herein, the growth of GaN films deposited on a novel nanocosine-patterned aluminum nitride (AlN) substrate is investigated by molecular dynamics simulation. This substrate contains concave patterning, which is conducive to better light-extraction performance, and GaN films with good crystal quality are obtained on the substrate. Results demonstrate that the degree of substrate patterning exerts a key effect on film quality. Case2 refers to the patterned model with an area change percentage of approximately 1.5. The proportion of wurtzite atoms in films deposited on Case2 nanocosine-patterned AlN substrates is higher than that in films deposited on unpatterned substrates at all temperatures. In addition, the former is more appropriate for low-temperature deposition to produce GaN thin films with better crystal quality. The film deposited on the nanocosine-patterned AlN substrate exhibits a shorter dislocation length and more complicated configuration. This condition is conducive to the postprocessing of the film, in contrast to the continuous and extensive dislocation defects in the deposited film on an unpatterned substrate. Choosing Case2 as an AlN patterning parameter for GaN growth at 2000 K helps to obtain high-quality GaN with a greater wurtzite structure content and fewer dislocations in simulation. Overall, this study investigates the deposition of GaN thin films at the nanoscale and obtains the temperature range and patterning information on the involved substrate for a high proportion of crystalline atoms, high density, low dislocation content, and low roughness to provide ideas for the high-quality growth of GaN thin films.