Improvement of the Crystalline Quality of InN Layers Grown on Sapphire (0001) by Surface Nitridation

Effect of substrate nitridation on the crystalline quality of InN layers grown on sapphire (0001) is investigated. The substrate nitridation and the growth of InN are performed using microwave-excited nitrogen as the reactive nitrogen source. It is realized that the epitaxial InN layers can be obtained by nitriding the substrate before the growth and that the crystalline quality of the InN layers is strongly dependent on the temperature of nitridation. The full-width at half maximum of x-ray rocking curve for InN (0002) diffraction of 140 arcsec is achieved by using nitridation.