Indium incorporation efficiency and critical layer thickness of (202¯1) InGaN layers on GaN

Abstract

In this study, the indium incorporation efficiency and critical layer thickness for misfit dislocation formation of thick (202¯1) oriented InGaN layers were investigated. InGaN layers with an indium content between 1.7% and 16% were grown by metalorganic vapor phase epitaxy. A reduced In-incorporation efficiency was found in comparison to (0001) oriented layers at 725°C. At lower growth temperature, the difference in incorporation efficiency between the two orientations is reduced. All (202¯1) InGaN layers, strained and relaxed with an In-content up to 12%, exhibit smooth surface morphologies with a rms roughness below 1 nm. In contrast to (0001) InGaN, hardly any strain is reduced by 3D-growth. The critical layer thickness for misfit dislocation formation of InGaN (202¯1) exhibits a behavior as predicted by the Matthews and Blakeslee model [J. W. Matthews and A. E. Blakeslee, J. Cryst. Growth 27, 118 (1974)]. Deviations, however, indicate that modifications of the formula are needed.