Investigation of indium incorporation into InGaN by nitridation of sapphire substrate in MOVPE

InGaN films on nitride-sapphire substrates were grown by metalorganic vapor phase epitaxy. Reciprocal space mappings of X-ray diffraction around the $(10\bar15)$ asymmetric plane were used to measure the accurate indium composition and in-plane strain of InGaN films. InGaN films with nitridation of sapphire substrates shows higher indium incorporation than without nitridation samples at low molar fraction ratio, TMIn/(TMIn+TEGa), of group-III MO source. However, the high molar fraction ratio region shows relatively low indium composition of InGaN. Most of the InGaN on nitrided sapphire substrates showed narrow FWHM of 2θ -ω and X-ray rocking curves and the surface flatness is improved, which indicates the improvement of crystal quality.