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

Abstract

The growth rate and properties of atomic layer deposited (ALD) Al2O3 thin films were examined by varying the water dose in the Al(CH3)3-H2O process at growth temperatures of 150–500°C. When the growth rate was followed as a function of water pulse time, it was found to saturate with both small and large water doses but the saturated level was substantially higher for the large water dose, 1.2 vs. 1.0 Å/cycle. This increase was attributed to an increased hydroxyl group density on the film surface after the 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 was minimal. No major differences were found in the properties of the films grown with small and large water doses.