P. De Almeida et al., Microstructure and growth modes of stoichiometric NiAl and Ni3Al thin films deposited by r.f.-magnetron sputtering, THIN SOL FI, 368(1), 2000, pp. 26-34
Intermetallic thin films of stoichiometric NiAl and Ni3Al have been deposit
ed onto n-type silicon (100) and nickel (110) substrates using r.f.-magnetr
on co-sputtering. The morphology and crystal structure of the thin films ha
ve been studied by transmission electron microscopy from planar-view and cr
oss-sectional samples. Chemical order has been assessed using nano-diffract
ion techniques. Superlattice reflections confirm a fully ordered structure
in both intermetallics. These NiAl and Ni3Al thin films are nanoscaled with
an average grain size ranging from 50 to 100 nm and exhibit fiber textures
in the (110) and (111)directions when deposited onto silicon. Granular- an
d heteroepitaxial relations have been observed when sputtering onto nickel
at high substrate temperature. A granular-heteroepitaxial mode of growth ex
hibiting the inverse Nishiyama-Wassermann relation (211)[211](B2) \\ (110)[
110](fcc) is observed in NiAl for the first time, whereas a single-crystall
ine heteroepitaxial growth relation of (110)[110](LI2) \\ (110)[110](fcc) i
s achieved in Ni3Al. The interface chemistry and surface topography have be
en studied by secondary ion mass spectroscopy and scanning tunneling micros
copy, respectively, indicating an oxygen-free layer of very low surface rou
ghness. The influence of the lattice matching and the deposition parameters
on the thin film microstructure and orientation are discussed. (C) 2000 El
sevier Science S.A. All rights reserved.