ATOMIC LAYER EPITAXY GROWTH OF TIN THIN-FILMS

TiN thin films were grown on soda lime glass substrates by atomic layer epitaxy. Two different chemical schemes were studied: a direct reaction between the alternately supplied TiCl4 and NH3, and a process employing a reducing zinc pulse given after the TiCl4 dose. The latter process was found to result in films with lower electrical resistivity. Resistivities as low as 50 mu Omega cm were measured for films grown with zinc at 500 degrees C while those prepared without zinc had resistivities of about 250 mu Omega cm. In both cases the contents of chlorine residues were below the detection limit of Rutherford backscattering spectrometry (RES), i.e., about 0.5 atom percent. In addition to RES and electrical measurements, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, nuclear resonance broadening, and reflectance spectra measurements were employed for the film characterization. The possible reasons for the major drawback of the process, the low growth rate of only about 0.2 Angstrom/cycle, are discussed.