NbAl3/Al microlaminated multilayer thin films were obtained by a laser abla
tion deposition method, using a KrF excimer laser (lambda = 248 nm) at a fl
uence of 7.6 J/cm(2). Films were deposited on Si substrates cooled during d
eposition by liquid nitrogen flow in order to minimize crystal growth and i
nterdiffusion between NbAl3 and Al layers. A helium gas flow to the middle
portion of substrate and target was maintained at varying ambient pressure
conditions (0, 100, 200 mtorr). Microstructures of the films produced were
studied by scanning electron microscopy (SEM), transmission electron micros
copy (TEM), and scanning transmission electron microscopy (STEM). With no h
elium backpressure, films exhibited an amorphous structure, but with increa
sing He pressure, the crystallinity of the films increased. TEM investigati
ons determined the average aluminum crystal size to be approximately 30 nm,
and each layer thickness to be 80 nm. STEM/EDS (electron dispersive spectr
oscopy) analysis showed no significant interdiffusion between NbAl3 and Al
layers. (C) 2001 Elsevier Science B.V. All rights reserved.