ERDA characterization of AlN thin films deposited by reactive pulsed laser method

The growth of metal-nitride thin films is of interest because of their important applications: AlN films are promising materials for microelectronics and optoelectronics devices. Several methods have been used to grow and deposit AlN thin films. In the present work the AlN thin films were deposited on Si wafers using reactive pulsed laser deposition from Al targets in nitrogen and from AlN target in vacuum and low pressure nitrogen. Two UV excimer laser sources were used: a ns system and, for the first time, a sub ps system. ERD analysis with ions has been systematically applied to determine the influence on the composition of the main deposition parameters: laser pulse duration, fluence and gas pressure. The ERDA measurements were carried out at 8.5 MV Tandem accelerator of IFIN-HH using a 63 Cu beam at 80 MeV. The detector consisted in a compact Δ E(gas)-E(solid) telescope, placed at 30 angle with respect to the beam. For the calibration of the telescope, the response of the passivated, ion implanted Si detector to different ions between H and Cu was measured. The quantitative analysis of ERDA spectra has been performed using our computer code SURFAN. A typical Δ E-Er spectrum is shown. Besides N and Al, in the film also present are: H, C and O. The energy spectra for all these components are shown and compared with the simulated spectra. Our analysis showed that the samples deposited using Al target consisted of AL only, with traces of AlN. The samples prepared using AlN target are stoichiometric. However, films deposited using the ns laser source contain a detectable amount of Al. (authors)