Shekhar Bhansali wrote:
>
> Dear Colleagues,
>
> I'm currently looking at TiNi SMA thin film fabrication for MEMS.  I was
> trying to find out whether any one has compared sputtered films using a
> single TiNi target v/s separate Ti and Ni targets.  If so what were the
> observations?
>
> What are the typical annealing conditions used for annealing the film i.e
> The heating rate, atmosphere and cooling rate?
>
> sincerely
>
> Shekhar Bhansali
> National Research Laboratory of Metrology
> 1-4 Umezono 1-Chome
> Tsukuba-shi
> Ibaraki 305 JAPAN
> Phone +81 298 54 4052       Fax:  =81 298 54 4135
>
>
It's better to use Ti:Ni target for Ar sputtering, whose exact
composition is fitted to the temperature you want the SMA to be
operated. This is very near 50%/50%, but as the two materials have
different sputtering rate this depend heavily on your equipment.
For anealing, there is two phases, first crystalization at high
temperature (800C), and after ageing at 500C for some hours.
To get precise informations on thin film SMA better read litterature and
specially the well documented publications of Prof. S. Miyazaki, of
Tsukuba University, Japan (for example Shape memory thin film of Ti-Ni
formed by sputtering, A. Ishida, A. Takei, S. Miyazaki, Thin solid
films, 228(1993) 210-214 and also MEMS proceedings 1994).
You may also have a look on the paper of Y. Nakamura, L. Buchaillot,...,
H. Fujita, at this year MEMS conference in Nagoya...
--
Dr. Franck CHOLLET
LIMMS/Fujita laboratory / CNRS/IIS-The University of Tokyo
7-22-1 Roppongi Minato-ku Tokyo 106 JAPAN
Tel/FAX : +81-3-3470-5103 e-mail : franck@fujita3.iis.u-tokyo.ac.jp