Kinetically controlled condensation boundary governing indium incorporation in InGaN metalorganic vapor phase epitaxy

We combine in situ synchrotron x-ray crystal truncation rod measurements with a binary Burton–Cabrera–Frank model to quantify indium incorporation during InxGa1−xN growth by metalorganic vapor phase epitaxy on GaN(0001). By distinguishing In adatoms from condensed droplets and incorporating coupled Ga–In incorporation kinetics, the model captures the intrinsically nonlinear dependence of indium composition xIn on flux and temperature. The critical In coverage corresponding to the maximum attainable In composition at a given temperature is determined by a kinetic balance between In adatom supply and incorporation capacity, defining a kinetically controlled condensation boundary that shifts with temperature and Ga flux. The model quantitatively predicts this boundary, consistent with independent measurements, and provides a framework for optimizing high-In-content InGaN growth while avoiding droplet formation.