1 research outputs found
Density-Functional Theory Molecular Dynamics Simulations and Experimental Characterization of a‑Al<sub>2</sub>O<sub>3</sub>/SiGe Interfaces
Density-functional
theory molecular dynamics simulations were employed to investigate
direct interfaces between a-Al<sub>2</sub>O<sub>3</sub> and Si<sub>0.50</sub>Ge<sub>0.50</sub> 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-Al<sub>2</sub>O<sub>3</sub> 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-Al<sub>2</sub>O<sub>3</sub> and SiGe