GRAPHOEPITAXIAL NITI SHAPE-MEMORY THIN-FILMS ON SI

Graphoepitaxial Ni50Ti50 films were grown on Si substrates by sputter deposition of an alloy target. The microstructure evolution of the fil m was investigated by hot stage atomic force microscopy. The topologic al features of the martensitic graphoepitaxial Ni50Ti50 films are dire ctly associated with etch pits on the surface of the silicon substrate and exhibit facets with well-defined preferential in-plane orientatio n. The highly ordered martensitic facets disappear as the film transfo rms to austenite at elevated temperatures. (C) 1998 American Institute of Physics.