Ion beam analysis of ion-assisted deposited amorphous GaN

Rutherford backscattering spectrometry and nuclear reaction analysis measurements were done using a 920 keV deuteron beam to investigate amorphous GaN films prepared on Si substrates bY an ion assisted deposition technique. Elemental concentrations and depth profiles of O, N, Ga were measured. Films deposited at 750 eV ion energy show that the Ga/N ratios are within 10% of unity and the Ga/O ratios are within 10-15%,, in the films having thicknesses ranging from 75 to 270 nm. Ga/N and Ga/O ratios in the films deposited at 800 and 900 eV were found to vary more than 10%. The Ga/N ratios of films produced at 400-750 eV are optimal for the production of single-phase a-GaN. There are only minor differences in the optical responses of these films and none at all in the Raman spectra within these levels of variation. Hydrogen analysis was also performed on the films using elastic recoil detection analysis with a 2.5 MeV4'He+ beam. This showed a surface enrichment of H in the thick films and low H concentration values of around 0.9%. (C) 2002 Elsevier Science B.V. All rights reserved.