Morphology and structure of indium nitride films

Growth processes of semiconducting indium nitride prepared by radiofrequency sputtering of a metallic target in a reactive nitrogen plasma have been studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Contrary to previous reports progressive nitridation of the target surface is observed [1] and is found to control film morphology and growth rate. Samples prepared from fully nitrided targets are exclusively c-axis oriented and polycrystalline, while other wurtzite planes persist when target nitridation is incomplete. The target process involved here requires the partial pressure of atomic nitrogen to be 10⁻⁴ Torr in the RF discharge region close to the target. Surface migration processes are also dependent on the target state. These phenomena are analyzed within the context of the structure zone model [2] while considering a unified approach to crystal growth habit [3].