title: Mechanisms of aluminium-induced crystallization and layer exchange upon low-temperature annealing of amorphous Si/polycrystalline Al bilayers.
abstract: Aluminium-induced crystallization (ALIC) of amorphous Si and subsequent layer exchange (ALILE) occur in amorphous-Si/polycrystalline-Al bilayers (a-Si/c-Al) upon annealing at temperatures as low as 165 degrees C and were studied by X-ray diffraction and Auger electron spectroscopic depth profiling. It follows that: (i) nucleation of Si crystallization is initiated at Al grain boundaries and not at the a-Si/c-Al interface; (ii) low-temperature annealing results in a large Si grain size in the continuous c-Si layer produced by ALILE. Thermodynamic model calculations show that: (i) Si can "wet" the Al grain boundaries due to the favourable a-Si/c-Al interface energy (as compared to the Al grain-boundary energy); (ii) the wetting-induced a-Si layer at the Al grain boundary can maintain its amorphous state only up to a critical thickness, beyond which nucleation of Si crystallization takes place; and (iii) a tiny driving force controls the kinetics of the layer exchange.
authors.affiliation: Max Planck Institute for Metals Research, Heisenbergstrasse 3, D-70569 Stuttgart, Germany.
authors.forename: J Y
authors.initials: JY
authors.lastname: Wang
authors.forename: Z M
authors.initials: ZM
authors.lastname: Wang
authors.forename: L P H
authors.initials: LP
authors.lastname: Jeurgens
authors.forename: E J
authors.initials: EJ
authors.lastname: Mittemeijer