Automation of Growth Rate Measurements for AlN/GaN Heteroepitaxial Structures with a Two-Dimensional Electron Gas Grown Using Ammonia Molecular Beam Epitaxy

Abstract— A method compatible with the growth process has been proposed for processing reflectograms recorded in situ by a laser reflectometer during the growth of III-nitride layers by ammonia molecular beam epitaxy (MBE). This method includes data filtering based on the fast Fourier transform (FFT). The cause of an additional high-frequency signal appearing and interfering with the registration of informative interference oscillations of reflected light intensity has been established as the oscillations of the holder with the sample installed on it during growth rotation. Sample rotation is a necessary technological technique in molecular beam epitaxy growth ensuring an increased uniformity of epitaxial film parameters. Comparison of the thickness values of individual III-nitride layers, as determined by the processing of reflectograms using software, with the values determined by scanning electron microscopy technique demonstrated a good agreement between the two methods. The software has been developed that automatically filters out high-frequency signals and determines the growth rate of individual III-nitride layers grown by ammonia molecular beam epitaxy.