Comment on “Analysis of hydroxyl group controlled atomic layer deposition of hafnium oxide from hafnium tetrachloride and water” [J. Appl. Phys. 95, 4777 (2004)].

In this comment we address issues raised by Puurunen in a paper comparing our model of atomic layer deposition (ALD) growth to Puurunen’s. The main conclusion is that our models are fundamentally different. In our model, we employ two differential equations, describing the deposition of HfO2 per cycle, and the creation rate of new OH groups per cycle. These two equations enable us to explain all observed ALD growth behaviors related to the concentration of OH nucleation sites. Puurunen’s model is essentially geometry based, and takes into account the concentration of nucleation sites, but contains no equation analogous to our second differential equation describing the evolution of OH groups from cycle to cycle. We then go on to address several specific points that Puurunen raised. [ABSTRACT FROM AUTHOR]