GROWTH OF HEXAGONAL GaN FILMS BY MOCVD USING NOVEL SINGLE PRECURSORS

摘要

The h-GaN films were grown on Si substrates by metal organic chemical vapor deposition (MOCVD) using novel single precursors, [(R)_2(N_3)Ga-(H_2NNH_2)] where R= CH_3 (I) and CH_3CH_2(II), that are volatile white solids. The spectroscopic data suggested that the precursors could be mononuclear Lewis acid-base adducts to saturate the coordination sphere of gallium metal with a neutral hydrazine ligand. The h-GaN films were deposited in the temperature range of 500 to 750 °C on Si (111) without any buffer layer or carrier gas. The crystalline structure, morphology and composition of the deposited h-GaN films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results show that the precursor with ethyl ligand should be better than that with methyl ligand concerning the crystallinity and stoichiometry of the deposited h-GaN films. The XRD indicated that the h-GaN films deposited using [Et_2(N_3)Ga-(H_2NNH_2)] were grown with the highly preferred orientation of [0001] direction. Other physical properties such as surface morphology, photoluminescence, and microstructure of the film are also discussed.