Numerical Modelling for the Experimental Improvement of Growth Uniformity in a Halide Vapor Phase Epitaxy Reactor for Manufacturing β-Ga2O3 Layers

• Published in: Crystals (Basel) 2022-12, Vol.12 (12), p.1790
• Main Authors: Pozina, Galia, Hsu, Chih-Wei, Abrikossova, Natalia, Hemmingsson, Carl
• Format: Article
• Language: English
• Subjects: computer simulation; Epitaxial growth; Epitaxial layers; Film thickness; Gallium oxides; Gas flow; Gases; Geometry; growth models; halide vapor phase epitaxy; Molecular beam epitaxy; Nitrogen; Precursors; Scanning electron microscopy; Simulation; Substrates; ultrawide bandgap semiconductors; Vapor phase epitaxy; Vapor phases; Wide bandgap semiconductors; β-Ga2O3
• ISSN: 2073-4352; 2073-4352
• DOI: 10.3390/cryst12121790

The development of growth processes for the synthesis of high-quality epitaxial layers is one of the requirements for utilizing the ultrawide band gap semiconductor Ga2O3 for high-voltage, high-power electronics. A halide vapor phase epitaxy (HVPE) process used to grow β-Ga2O3 layer was optimized by modifying the gas inlet, resulting in improved growth uniformity. A conventional tube acting as an inlet for the Ga precursor GaCl gas was replaced with a shower head with four outlets at 45 degrees to the horizontal axis of the reactor. The modification was performed based on numerical calculations of the three-dimensional distribution of gases inside the growth chamber with different designs of the GaCl precursor inlet. It was shown that variation in the Ga/O ratio over the substrate holder was ~10% for a shower head compared with ~40% for a tube. In addition, growth with a tube leads to the film thickness varying by a factor of ~4 depending on the position on the holder, whereas when using a shower head, the thickness of the grown Ga2O3 layers became much more uniform with a total spread of just ~30% over the entire substrate holder.