Fourier analysis applied on in situ laser reflectometry during III-nitride metal organic chemical vapor deposition growth

In this article we present the Fourier analysis of kinetic reflectometry spectra acquired during metalorganic chemical vapor deposition. We can show that offset errors due to background radiation can be completely removed by the method itself without using filters or lock-in amplifiers. Additionally, calibration of the reflected intensity is needed as long as the response of the detector is linear to the reflected intensity of the sample. By analyzing the time dependent part of the signal growth rate, layer thickness and the refractive index of the growing layer can be deduced. We demonstrate that, by applying the method to the GaN:Mg $δ$-doping process, it is possible to obtain accurate information about the time, optical properties, and thickness of the grown multilayers with a resolution down to the monolayer range.