Intrinsic stress evolution during amorphous oxide film growth on Al surfaces

Abstract

The intrinsic stress evolution during formation of ultrathin amorphous oxide films on Al(111) and Al(100) surfaces by thermal oxidation at room temperature was investigated in real-time by in-situ substrate curvature measurements and detailed atomic-scale microstructural analyses. During thickening of the oxide a considerable amount of growth stresses is generated in, remarkably even amorphous, ultrathin Al 2 O 3 films. The surface orientation-dependent stress evolutions during O adsorption on the bare Al surfaces and during subsequent oxide-film growth can be interpreted as a result of (i) adsorption-induced surface stress changes and (ii) competing processes of free volume generation and structural relaxation, respectively. V

Massive Ag migration through metal/ceramic nano-multilayers: an interplay between temperature, stress-relaxation and oxygen-enhanced mass transport

“…However, during the first stage of heating up to about 200 1C, the compressive stress state of the confined Ag remains relatively constant (Fig. 6), which suggests that compressive stress generation by the thermal expansion mismatch is probably counteracted by tensile stress generation due to the annihilation of growth defects (and possibly also by the annihilation of grain boundaries due to domain coarsening 20,36 ). The expected accumulation of compressive stresses in the confined Ag layers (due to the thermal expansion mismatch) proceeds in the temperature range of 200 1C o T o 280 1C.…”

Effect of structural order on oxidation kinetics and oxide phase evolution of Al–Zr alloys

“…The oxide layer produced on the alloy can be amorphous or crystalline, depending on numerous factors, such as the difference between the bulk Gibbs energies of the amorphous and crystalline states of the competing oxide phases, the participating surface and interface energies, the initial lattice mismatch with the parent substrate, the oxide layer thickness, the alloy composition, and the oxidation temperature [9][10][11][12][13][14][15][16]. Because of the relatively large free volume and bond flexibility of amorphous oxides, growth stresses and thermally induced stresses may be partly accommodated by viscous flow, thereby promoting adhesion across the substrate-film interface [9,[17][18][19][20]. Moreover, the absence of grain boundaries and other lattice defects in amorphous oxides decreased the number of fast short-circuit diffusion paths, thereby promoting the formation of chemically and structurally homogeneous oxide layers of highly uniform thicknesses.…”

Oxidation kinetics of nanocrystalline Al thin films

“…To facilitate its application, moreover, much work has been done to investigate the thermal oxidation of single-crystal or polycrystalline Al and its oxidation kinetics at relatively high temperatures above 400°C (Zhang et al, 2015;Cai et al, 2014;. Generally, an ultrathin amorphous oxide layer is formed upon heating with limited thickness less than 4 nm, dependent on the oxygen partial pressure (Cai et al, 2014;Reichel et al, 2006,;Flötotto et al, 2014;Cai et al, 2012;Lanthony et al, 2012;Reichel et al, 2008a). The oxidation kinetics can be influenced by the temperature, which follows the parabolic oxidation rate rule at around 400°C, the paralinear law between 450 and 600°C, and the asymptotic law at 600°C (Reichel et al, 2008b;Reichel et al, 2006;Libisch et al, 2012;Gulbrbnsen and Wysong, 1947;Smeltzer, 1956).…”