Influence of lattice constraint from InN and GaN substrate on relationship between input mole ratio and solid composition of InGaN during MOVPE

Abstract

Thermodynamic analyses incorporating the contribution of lattice constraint from the substrates were carried out to understand the relationship between input In mole ratio and solid composition of stress-free InGaN, InGaN on GaN and InGaN on InN during metalorganic vapour phase epitaxy. The calculated results suggest that a compositionally unstable region is found at the InN-rich region for InGaN on GaN at high temperatures, while that for InGaN on InN can be seen at the GaN-rich region due to the lattice constraint from the substrate. These results imply that incorporating the contribution of lattice constraint is indispensable to predict the thermodynamic properties of such materials.

Growth mode of InGaN on GaN (0001) in MOVPE

“…Calculations, e.g. of Kangawa et al [15] confirmed indeed that strain inhibits a higher indium incorporation. It should be noted that binodal decomposition cannot explain this behaviour, because then the decomposition should occur right from the start of the layer growth.…”

Analysis of compositional instability of InGaN by Monte Carlo simulation

“…To determine the relationships between growth conditions and compositional fluctuation, we have performed thermodynamic analyses of InGaN growth by MOVPE [3,4]. The results of calculations suggest that the compositional instability was enhanced at high temperatures in the case of high indium input partial pressure.…”

Theoretical analyses of In incorporation and compositional instability in coherently grown InGaN thin films

“…"growth", "unstable (there is more than one composition for one input condition.)" and "etching" [14]. Here, a thin film with a unique composition would grow in case of "growth" condition.…”