Density functional theory study of initial stage of ZrO_2 atomic layer deposition on Ge/Si(100)-(2x1) surface

摘要

The reaction mechanisms of ZrCl_4 adsorption and dissociation on Ge/Si(100)-(2x1) surface as the initial stage oi ZrO_2 atomic layer deposition process are investigated with density functional theory (DFT). The Si-Si, Si-Ge and Ge-Ge one-dimer cluster models are employed to represent Ge/Si(100)-(2x1) surface with different Ge composition. The reaction of ZrCl_4 with hydroxylated Ge/Si( 100)-(2x1) surface forms a bridged ZrCl_2 site, while on H-passivated surface, ZrCl_3 site is formed. The reaction energy barrier of ZrCl_4 with H-passivated SiGe surface is much higher than ZrCl_4 with hydroxylated SiGe surface, which indicates that reaction proceeds more slowly on H-passivated surface than on OH-terminated surface. In addition, adsorption of ZrCl_4 is favorable on Ge surface atoms than on Si surface atoms.