Growth kinetics and mass transport mechanisms of GaN columns by selective area metal organic vapor phase epitaxy

Three-dimensional GaN columns recently have attracted a lot of attention as the potential basis for core-shell light emitting diodes for future solid state lighting. In this study, the fundamental insights into growth kinetics and mass transport mechanisms of N-polar GaN columns during selective area metal organic vapor phase epitaxy on patterned SiOx/sapphire templates are systematically investigated using various pitch of apertures, growth time, and silane flow. Species impingement fluxes on the top surface of columns J(top) and on their sidewall J(sw), as well as, the diffusion flux from the substrate J(sub) contribute to the growth of the GaN columns. The vertical and lateral growth rates devoted by J(top), Jsw and Jsub are estimated quantitatively. The diffusion length of species on the SiOx mask surface lambda(sub) as well as on the sidewall surfaces of the 3D columns lambda(sw) are determined. The influences of silane on the growth kinetics are discussed. A growth model is developed for this selective area metal organic vapor phase epitaxy processing. (C) 2014 AIP Publishing LLC.