Density functional theory study of adsorption and dissociation of HfCl_4 and H_2O on Ge/Si(100)-(2X1): Initial stage of atomic layer deposition of HfO_2 on SiGe surface

摘要

We have investigated adsorption and dissociation of water and HfCl_4 on Ge/Si(100)-(2 X 1) surface with density functional theory. The Si-Ge heterodimer and Ge-Ge homodimer are employed to represent the Si_(1-x)Ge_x surface. The activation energy for adsorption of water on Ge-Ge homodimer is much higher than that on Si-Ge heterodimer. No net activation barrier exists during the adsorption of HfCl_4 on both SiGe surface dimers. The differences in the potential energy surface between reactions on Si-Ge and Ge-Ge dimers are due to different bond strengths. It should also be noticed that the activation energy for HfCl_4 is quite flat, thus HfCl_4 adsorbs and dissociates on Ge/Si(100)-(2 x 1) easily.