Indium segregation in MOCVD InGaN layers studied by medium energy ion scattering

The long term stability of InGaN based light emitting- and laser-diodes is potentially compromised by phase separation and indium interdiffusion. Medium energy ion scattering has been used to investigate the diffusion of indium within In0.25Ga0.75N/GaN structures at 950°C. Comparison of the aligned and random ion scattering data for the as-deposited InGaN layer show that ca. 15% of the indium atoms are interstitial. Annealing at 950°C causes decomposition of the InGaN layer into InN and a range of lower indium content ternary phases.