Influence of hydrogen and TMIn on indium incorporation in MOVPE growth of InGaN layers

The InGaN layers were grown using the Metalorganic Vapour Phase Epitaxy on bulk GaN substrates in a stop-and-go-mode (30 s growth, 30 s stop) and then examined using X-ray Diffraction (XRD), Photoluminescence (PL), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The experiment was done in order to study an influence of hydrogen and TMIn flows during the growth-breaks on the InGaN layer. It was found that the presence of hydrogen during the breaks removes indium atoms from the already grown InGaN layer and delays In-incorporation into the subsequent one. As a result, instead of having about 18% of In in the continuously grown InGaN, we have only about 6% (average In-content) and the layer is thinner by more than 20%. In the case of having simultaneously H2 and TMIn flows on during the breaks, we get three times less of In-atoms torn away and the layer has the thickness unchanged. The simultaneous presence of TMIn and H2 also gave much smaller surface roughness as compared to the situation when only H2 was on during the breaks.