title: Origin of Indium Diffusion in High-k Oxide HfO2.
abstract: Indium (In) out-diffusion through high-k oxides severely undermines the thermal reliability of the next generation device of III-V/high-k based metal oxide semiconductor (MOS). To date, the microscopic mechanism of In diffusion is not yet fully understood. Here, we utilize angle resolved X-ray photoelectron spectroscopy (ARXPS) and density functional theory (DFT) to explore In diffusion in high-k oxide HfO2. Our ARXPS results confirm the In diffusion through as-prepared and annealed HfO2 grown on InP substrate. The theoretical results show that the In diffusion barrier is reduced to ∼0.88 eV in the presence of oxygen vacancies (VO), whereas this barrier is as high as ∼4.78 eV in pristine HfO2. Fundamentally, we found that the high feasibility of In diffusion is owing to In nonbonding with its neighboring atoms. These findings can be extended to understand the In diffusion in other materials in addition to HfO2.
authors.affiliation: Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University , Tianjin 300071, China.
authors.forename: Yaoqiao
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University , Tianjin 300071, China.
authors.forename: Changhong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University , Tianjin 300071, China.|Department of Materials Science and Engineering, University of Texas at Dallas , Richardson, Texas 75080, United States.
authors.forename: Hong
authors.initials: H
authors.lastname: Dong
authors.affiliation: Department of Materials Science and Engineering, University of Texas at Dallas , Richardson, Texas 75080, United States.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Wallace
authors.affiliation: Department of Materials Science and Engineering, University of Texas at Dallas , Richardson, Texas 75080, United States.
authors.forename: Kyeongjae
authors.initials: K
authors.lastname: Cho
authors.affiliation: Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University , Tianjin 300071, China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Wang
authors.affiliation: Department of Electronics and Tianjin Key Laboratory of Photo-Electronic Thin Film Device and Technology, Nankai University , Tianjin 300071, China.|Department of Materials Science and Engineering, University of Texas at Dallas , Richardson, Texas 75080, United States.
authors.forename: Weichao
authors.initials: W
authors.lastname: Wang
keywords: HfO2; III-V/high-k oxide interface; first-principles calculation; high-k oxides; indium diffusion