Theoretical investigation of the effect of growth orientation on indium incorporation efficiency during InGaN thin film growth by metal-organic vapor phase epitaxy

The effect of growth orientation on In incorporation efficiency in InGaN films grown by metal-organic vapor phase epitaxy (MOVPE) is theoretically investigated. We propose a new theoretical model that explains the role of the surface N-H layer in In incorporation based on first-principles calculations. During III-nitride MOVPE, N-terminated reconstruction with N dangling bonds passivated by H is stable. A surface N-H layer that covers a group-III (In, Ga) atomic layer prevents In atoms from desorbing and being replaced by Ga atoms. In incorporation is therefore more efficient for higher N-H layer coverage and stability. To investigate this relationship, the enthalpy change for the decomposition of a N-H layer was calculated. This enthalpy change which depends on growth orientations is in good agreement with the experimental In content.