Analysis of mass transport mechanism in InGaN epitaxy on ridge shaped selective area growth GaN by metal organic chemical vapor deposition

In this work, the evolution of the InGaN layer growth on the ridge shaped GaN was studied. A mass transport model was presented to simulate the epitaxy process of the InGaN layer. The model consisted of two consecutive components, gas-phase diffusion process and surface diffusion process. The mean lifetime of adatoms on epitaxial surface was associated with their reaction rate in this model. An InGaN layer on ridge shaped GaN, including (0002) and {112¯2} facets, was grown by metal organic chemical vapor deposition to confirm the mass transport model. Gradient indium content distribution and inhomogeneous thickness of the InGaN layer were observed. Simulation of the InGaN layer growth process was performed by finite difference method with the mass transport model. By analyzing the results from calculations and experiments, the origins of the InGaN layer characteristics were attributed to the two diffusion components in the growth process. Surface diffusion resulted in the inhomogeneous thickness and gas-phase diffusion chiefly led to the gradient indium content. In addition, the adatoms reaction rate on epitaxial surface determined their mean lifetime as speculated by the analysis. The demonstration of the growth process of InGaN layer offers valuable insight in obtaining high efficiency white light emitting diodes by selective area growth technology.