Hi,
  Pin holes are always a problem with sputtered films. I think that you may have
to heat the substrate during deposition or switch to an energetic ion deposition
technique.

Check the literature,
Mike


>>> cheongwei2000@yahoo.com 4/18/2004 7:05:40 AM >>>
Hi!

Thank you very much for your reply and advices!

Below are some details of the sputtering depositions
condition:


           RuO2           Pt           Bismuth
titanate
          -----           ---
----------------
Target     RuO2           Pt           Bi3Ti4O12
(1" dia.)

Power(W)    80            50            100

Distance
fr subst.   4             4              4
to target
(cm)

O2/(O2+Ar)  25%           0%             50%

Film
thickness   57            50              90
(nm)      (on Si)      (on Si)        (on Si/SiO2)

Annealing  800 0C       650 0C           650 0C
Temp.
(30 mins)

Subst.Temp Ambient      Ambient         Ambient
          (~100 0C)     (~50 0C)       (~100 0C)


I have tryed so many ways to solve the short circuit
problem, including replace the Pt by RuO2 as bottom
electrode, which the Pt film is more rougher
(30-50nm)than the RuO2 film (~11nm). However, the
problem still existed.

For the ferroelectric film characterisations, i just
went through the XRD analysis. The results showed that
the film present the perovskite structure as what
desired.

Now, what i suspected that the failure is due to the
bottom electrode films and ferro films are too thin.
As in this situation, the interdifussion between
bottom electrode and ferro films might be happened.

I have no experience in fabricating the thin films
capacitor or devices. Hopefully can get more
suggestions or advices from you! Thanks a lot!

from ,
Chong Cheong Wei
Institute of Microengineerng and Nanoelectronics
University Kebangsaan Malaysia


--- Tetsuya Kishino 
wrote:
> Hi,
>
> I think you should write the film thickness and
> deposition conditions.
>
> If your film is dense and has no pin hole,....
> 1.Poor coverage:
>  The ferroelectric film may have discontinuity at
> the edge of the bottom electrode.
> 2. Titanium diffusion:
>  Ti can easily diffuse into the titanate film.  We
> had a lot of short capacitor problems when
> depositting (Ba,Sr)TiO3 on Ti electrode. Of course,
> it depends on the thickness of the Pt.
>
> > Subject: [mems-talk] Short circuit capasitor thin
> films
> > Message: 5
> >
> > Dear all,
> >
> > I try to deposit the ferroelectric thin films
> (bismuth
> > titanate)on substrates Si/SiO2/Ti/Pt and
> Si/SiO2/RuO2 by RF
> > magnetron sputtering. But both the samples facing
> the problem
> > of "short circuit capasitor" after the deposition
> of top
> > electrode. May i know what are the possible
> reasons of the problem?
> >
> > Thanks!
> >
> > from,
> > Chong Cheong Wei
>
>
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