Thin films of
were prepared on various substrated of MgO(100),
, and
by using off-axis magentron sputtering methods and annealing in-situ. The prarameters of film fabrication processes had been optimized through a "follow the lcoal maxima" strategy to yield good quality films in therms of the critical temperature
and the critical current density
. Optimizedproecsses employing a plane magndtron and an cylindrical magnetron yielded
>90K along with
A/
at 77K and > 2
A/
at 5K. The sampels, however, showed degradationinthe properties, after chemical etching for fabrication of microbridges with the line width of 2-10 mocrons. In particular, the value of
for the microbridges of 2microns was as small as 80%. The degradation was strongly dependent on the line width through a formula :
(e)=
)b) [1-a exp(-1000 bL)} where
(e) and
(b) are the values of
in the absolute scale measured after and before chemical etching, respectively and L is the line width in mm. By utilizing a best fitting technique, the proper constant values of a and to b were found as exp(-1.2) and 0.22, respectively. This formula was very useful in estimatiing the upper limit of the device operationtemperature.
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