CHEMICAL-VAPOR-DEPOSITION PRECURSOR CHEMISTRY .5. THE PHOTOLYTIC LASER DEPOSITION OF ALUMINUM THIN-FILMS BY CHEMICAL-VAPOR-DEPOSITION

Thin films of very high purity aluminum were formed from the laser pho tolysis of trimethylamine alane (TMAA) using both ultraviolet (pulsed nitrogen) and visible (argon ion) laser irradiation on a variety of su bstrates including gold, Si(111), GaAs(110) and Teflon (PTFE). At thic knesses of up to 1 mu m, nearly linear growth rates of 377 Angstrom s( -1) and 112 Angstrom s(-1) were observed. The formation of volatile sp ecies formed during the deposition of aluminum from TMAA was investiga ted by quadrupole mass spectrometry (QMS) of the reactant gas stream. The highest intensity post-deposition mass fragments were observed at m/z 58, 43 and 42 amu corresponding to [NC3H8](+), [NC2H5](+) and [NC2 H4](+), respectively. These species arise from the dissociation and su bsequent fragmentation of the trimethylamine ligand from the starting TMAA complex. Semi-empirical quantum chemical calculations (MNDO) for TMAA provided further support that photolysis of this precursor should result in principally ligand dissociation processes since the LUMO or bital is primarily an aluminum-nitrogen antibonding interaction. The d eposited materials were also characterized by X-ray emission spectrosc opy (XES), scanning electron microscopy (SEM), and Laser Microprobe Ma ss Analysis (LAMMA) techniques.