Surface deformation of the InGaN thin films deposited on a sapphire substrate

The study reports a research into the mechanical properties of InGaN films deposited on sapphire by the metalorganic chemical vapor deposition method, being, as such, related to the very recent construction of the blue-emitting laser diode. The surface deformation of the films has been investigated by means of depth-sensing indentation experiments. Undoped films and those doped with Mg have been examined. The analysis of the depth-sensing indentation data, providing complete information on the surface deformation of InGaN films, has been based on the energy principle of indentation. The results revealed that the hardness of InGaN is lower than that of sapphire crystal. On the other hand, InGaN was found to posses considerable toughness. The surface features appearing around the residual impressions were observed using atomic force microscopy. (C) 1997 Elsevier Science S.A.