Homoepitaxial growth rate measurement and surface morphology monitoring of MOVPE-grown Si-doped (1 0 0) β-Ga2O3 thin films using in-situ reflectance spectroscopy

Abstract

We investigate Si-doped β-Ga2O3 layers grown by metalorganic vapor phase epitaxy (MOVPE) on (100) β-Ga2O3 semi-insulating substrates with the reflection spectrum incident normally onto the substrate surface. The reflectance spectrum transformed into the autocorrelation domain shows a more pronounced Fabry-Pérot oscillation than the raw spectrum, from which one can easily estimate the growth rate and the growth mode based on the period, and the damping behavior of the spectrum, respectively. The observed oscillation contributes to the refractive index difference between the bulk substrate and the grown film caused by the incorporated impurities and different preparation techniques. The high sensitivity of the reflectance spectroscopy is demonstrated to be an advantage as a powerful growth process monitoring tool.