Dual-superlattice calibrations for group-III species in III-V semiconductor epitaxial structure growth

High-resolution x-ray diffraction analysis of superlattice structures is often used to calibrate epitaxial growth systems. In most cases, systematic errors introduce biases that overwhelm the random measurement error, thus requiring a series of calibrations to be completed in order to target a narrow range of materials. Structures consisting of two superlattices grown with a single pair of group-III sources offer significant improvements in calibrating group-III growth rates over conventional single-superlattice structures. It is shown that these dual superlattices avoid pitfalls associated with uncertainty and variability in the lattice constants and elastic constants of the constituent materials as well as those of the substrate. Analyses of the high-resolution x-ray diffraction spectra for several different binary/binary, ternary/binary, and quaternary/binary superlattices provide accurate determination of group-III beam fluxes, leading to the capability of reproducing growth rates with accuracy of within 1%. (c) 2014 American Vacuum Society.