GROWTH OF GAN LAYER FROM THE SINGLE-SOURCE PRECURSOR (ET2GANH2)(3)

In recent years, there has been a great interest in new routes for dep ositing GaN films in the application of III-V semiconductors. We repor t herein on the deposition of highly crystalline GaN films by low-pres sure MOCVD (in the low-temperature range of 500-700 degrees C and the pressure range of 77-177 mbar) using the single-source precursor (Et2G aNH2)(3). This process was investigated for a variety of substrates (S i(100) and polycrystalline Al2O3) using a cold wall chemical vapor dep osition reactor. The thickness of films grown under these conditions r anged from 6 to 8 mu m, and the growth rates varied from 7 to 8 mu m/h . Films deposited at lower temperatures (500-550 degrees C) had a pale yellowish color and were amorphous. At 600 degrees C slightly gray co lored films were obtained, while above 650 degrees C high-quality crys talline films were formed, which show diffraction patterns characteris tic of the hexagonal wurtzite structure. The films are consistent with the 1:1 stoichiometry of GaN and have carbon and oxygen as impurities ; however, cracks were not evident on the surface by SEM examination u p to a magnification of 30000. In contrast, samples of GaN deposited u nder high-vacuum conditions (up to 10(-2) mbar) have neither a 1:1 sto ichiometry nor a smooth surface morphology. Atomic force microscopy, s canning electron microscopy, Auger electron microscopy, and energy-dis persive X-ray analyses were used for the study of the structure, compo sition, and morphology of the films.