Effect of water dose on the atomic layer deposition rate of oxide thin films

The growth rate and properties of atomic layer deposited (ALD) Al2O3 thin f ilms were examined by varying the water dose in the Al(CH3)(3)-H2O process at growth temperatures of 150-500 degrees C. When the growth rate was follo wed as a function of water pulse time, it was found to saturate with both s mall and large water doses but the saturated level was substantially higher for the large water dose, 1.2 vs. 1.0 Angstrom/cycle. This increase was at tributed to an increased hydroxyl group density on the film surface after t he water pulse. The effect of the water dose was examined also in other ALD oxide processes where in most cases the growth rate increased by 24 to 86% , in the best cases even doubled, though in a few other cases the effect wa s minimal. No major differences were found in the properties of the films g rown with small and large water doses. (C) 2000 Elsevier Science S.A. All r ights reserved.