Jc. Chen et al., GROWTH-KINETICS OF AMORPHOUS INTERLAYERS BY SOLID-STATE DIFFUSION IN ULTRAHIGH-VACUUM DEPOSITED POLYCRYSTALLINE GD THIN-FILMS ON (001)SI, Journal of applied physics, 84(11), 1998, pp. 6083-6087
The growth kinetics of amorphous interlayer (a-interlayer) formed by s
olid-state diffusion in ultrahigh vacuum deposited polycrystalline Gd
thin films on (001)Si have been investigated by cross-sectional transm
ission electron microscopy. The growth of the a-interlayer was found t
o follow a linear growth law initially. The growth then slows down and
deviates from a linear growth law. The result clearly indicated that
the growth at early stage is consistent with an interface-reaction-con
trolled growth model rather than diffusion limited. The activation ene
rgy of the linear growth and maximum thickness of the a-interlayer wer
e measured to be about 0.37 eV and 6.6 nm, respectively. Following the
growth of amorphous interlayer, epitaxial hexagonal GdSi2-x was found
to form at the a-interlayer/(001)Si interface at 225 degrees C. The r
elatively small lattice mismatch between GdSi2-x and (001)Si compared
to other RESi2-x (RE=rare-earth metal) and (001)Si systems facilitates
the epitaxial growth of GdSi2-x on (001)Si, which in turn hampers the
further growth of a-interlayer. (C) 1998 American Institute of Physic
s. [S0021-8979(98)01023-8].