[i] R. A. Fischer, A. Miehr, E. Herdtweck, M. R. Mattner, O. Ambacher, T. Metzger, E. Born, S. Weinkauf, C. R. Pulham, S. Parsons, Chem.-
Eur. J., 1996, 2, 1353.
[ii] H. Sussek, O. Stark, A. Devi, H. Pritzkow and R. A. Fischer, J. Organomet. Chem., 2000, 602, 29.
Dimethylgallium azide GaMe2(N3) has been used as a single-source precursor for the growth of polycristalline GaN films with strong (0002) preferred orientation at 450-650°C temperature and 0,2-3·10-4 Torr pressure on GaAs (100), GaAs (111), sapphire (0001) and quartz. Films grown at 475°C were continuous and had bandgap ~3.3 eV; films grown at higher temperature were darker and had cracks, the darkening effect could be partially suppressed by the addition of dimethylhydrazine. The calculated activation energy for the deposition reaction is 15 kcal/mol (63kJ/mol). [467]
Diethylgallium azide GaEt2(N3)and its adducts with MeNH2 and MeHNNH2 have been used for the CVD deposition of stoichiometric GaN films on Si(111) substrates. Films were hexagonal by XRD and had [0001] preferred orientation. []
Diethylgallium azide has been applied for the growth of pure GaN at low growth temperature by thermal chemical vapor deposition (CVD). [444]
Bisazido(dimethylamino-propyl) gallium Ga(N3)2[(CH2)3NMe2] (BAZIGA) has been proposed as a single molecule precursor for the organometallic vapor phase epitaxy (OMVPE) of GaN thin films. In the cold-wall CVD reactor, epitaxial films of GaN, transparent in appearance and stoichiometric in composition, were deposited on c-plane sapphire, in the absence of ammonia, above 1073 K, under low pressures (between 0.080 and 100.0 mbar). Dense, amorphous, and very smooth films were grown at temperatures as low as 773 K. The influence of substrate temperature, reactor pressure, and the effect of small quantities of additional ammonia, on the growth rate and the film properties, were studied. The films were characterized by high-resolution X-ray diffraction (XRD) (full width at half maximum (FWHM) of the 0002 GaN rocking curve of 130 arcsec), X-ray reflectometry, scanning electron microscopy (SEM), atomic force microscopy (AFM) (root mean square roughness of 1.9 nm), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), Rutherford backscattering (RBS) (Ga/N = 1:1 ± 0.05), and photoluminescence (PL) measurements (band edge luminescence at 3.45 eV and FWHM of 0.22 eV at 300 K).[447]
The growth kinetics of GaN thin films using BAZIGA was studied in a cold wall CVD reactor. Transparent smooth stoichiometric epitaxial GaN films (FWHM of the a-GaN 0002 rocking curve = 129.6 arcsec) were grown on c-plane sapphire substrates in the temperature range 597-1047°C, at high growth rates (up to 4 µ/hr). Film growth was studied as a function of substrate temperature, reactor pressure, and presence or absence of additional source of nitrogen source (ammonia); high quality films obtained even without using NH3. Room temperature PL spectroscopy of GaN films exhibited the correct near band edge luminescence at 3.45 eV.[448]