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

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 beta-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 similar to 10% for a shower head compared with similar to 40% for a tube. In addition, growth with a tube leads to the film thickness varying by a factor of similar to 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 similar to 30% over the entire substrate holder.