Enhancing the nucleation of palladium atomic layer deposition on Al2O3 using trimethylaluminum to prevent surface poisoning by reaction products

Metal atomic layer deposition (ALD) on oxides can display long nucleation periods and high growth temperatures that may be caused by surface poisoning by reaction products. Exposures of trimethylaluminum (TMA) during Pd ALD using Pd (hfac)(2) and formalin on Al2O3 surfaces can shorten the nucleation period and reduce the growth temperatures. Fourier transform infrared spectroscopy studies indicate that TMA removes Al(hfac)* species that block surface sites. Pd ALD nucleates more readily and grows at lower temperatures because higher temperatures are not needed to desorb Al (hfac)* species. Transmission electron microscopy analysis shows the differences between Pd ALD films deposited with and without TMA. (C) 2009 American Institute of Physics. [doi:10.1063/1.3238558]