Initial growth stage of GaN on Si substrate by alternating source supply using dimethyl-hydrazine

Abstract

Alternating source supply mehtod of Ga an N sources is proposed to control the initial nitridation stages for the direct growth of GaN on Si. The initial growth stages under the alternating source supply are characterized by the X-ray photoelectron spectroscopy and the atomic force microscope. A suppression effect for the nitridation of Si surface by an excess Ga supply is investigated. The systematic analysis of the spectra shows that the Ga atoms play an important role in both the removal of Si native oxides and the suppression of the nitridation during the initial growth stages. The atomic force microscopic images show that the surface morphologies depend on the substrate temperature of the initial growth stages. The surface morphology of the sample grown at 500°C is smoother than the one grown at 600°C. This implies that there is a possibility to realize the growth conditions for the pseudo Stranski-Krastanov growth mode without Si nitridation at the initial stages in a low temperature region in the alternating source supply method for the direct growth of III–V nitrides on Si.