Demonstration of crystal-vapor equilibrium leading to growth blockade of GaN during selective area growth

► Growth of GaN by Selective Area Growth (SAG-) Hydride Vapor Phase Epitaxy (HVPE). ► High concentration of hydrogen in the carrier gas revealed domains of nil growth rates. ► Thermodynamic and kinetic analyses of the grown (0001) GaN layers led to analysing the reasons leading to a blocking of the GaN structures. ► Growth was performed on both unmasked (0001) GaN and patterned GaN/c-plane sapphire substrates. ► Long-time HVPE runs were performed to identify the prevailing growth mechanism.