title: Density-Functional Theory Molecular Dynamics Simulations and Experimental Characterization of a-Al₂O₃/SiGe Interfaces.
abstract: Density-functional theory molecular dynamics simulations were employed to investigate direct interfaces between a-Al2O3 and Si0.50Ge0.50 with Si- and Ge-terminations. The simulated stacks revealed mixed interfacial bonding. While Si-O and Ge-O bonds are unlikely to be problematic, bonding between Al and Si or Ge could result in metallic bond formation; however, the internal bonds of a-Al2O3 are sufficiently strong to allow just weak Al bonding to the SiGe surface thereby preventing formation of metallic-like states but leave dangling bonds. The oxide/SiGe band gaps were unpinned and close to the SiGe bulk band gap. The interfaces had SiGe dangling bonds, but they were sufficiently filled that they did not produce midgap states. Capacitance-voltage (C-V) spectroscopy and angle-resolved X-ray photoelectron spectroscopy experimentally confirmed formation of interfaces with low interface trap density via direct bonding between a-Al2O3 and SiGe.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Evgueni
authors.initials: E
authors.lastname: Chagarov
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Kasra
authors.initials: K
authors.lastname: Sardashti
authors.affiliation: Applied Materials , Santa Clara, California 95054, United States.
authors.forename: Tobin
authors.initials: T
authors.lastname: Kaufman-Osborn
authors.affiliation: GlobalFoundries , Malta, New York 12020, United States.
authors.forename: Shailesh
authors.initials: S
authors.lastname: Madisetti
authors.affiliation: Department of Nanoscale Science and Engineering, University at Albany-State University of New York , Albany, New York 12222, United States.
authors.forename: Serge
authors.initials: S
authors.lastname: Oktyabrsky
authors.affiliation: GlobalFoundries , Malta, New York 12020, United States.
authors.forename: Bhagawan
authors.initials: B
authors.lastname: Sahu
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Kummel
keywords: Al2O3; DFT; SiGe; ab initio; high-k oxide; molecular dynamics; oxide-semiconductor interface