New approach to the X-ray diffraction analysis of test structures during flow calibration in epitaxial growth reactors

Abstract

The high-resolution X-ray diffractometry (HRXRD) technique is known as a powerful tool for analyzing epitaxial heterostructures. However, standard analysis procedures do not allow the layer growth time to be used as a fixed parameter during HRXRD spectra analysis. The growth time in modern facilities is measured with a high degree of accuracy, which increases the reliability of HRXRD analysis particularly in the case of spectra with reduced quality or complex heterostructures consisting of a large number of individual homogeneous layers. A new algorithm is based on using flow rates of deposited components as variable parameters, while the layer growth times are taken as fixed parameters. A particular feature of this new approach is associated with the fact that the known growth time for each heterostructure layer is directly included into the algorithm for adjustment of the calculated spectrum to the experimental X-ray diffraction spectrum (HRXRD). The flows of deposited layers are variable parameters and, thus, the algorithm turned out to be very efficient for calibrating flow controllers in epitaxial growth reactors. The algorithm allows for reliable estimation of the flow even in the case of poorly informative HRXRD spectra.