At a high deposition rate, the impingement rate of Cr on the substrate will
be higher than the impingement rate of background gases. But at 10^-7 Torr
I still don't think oxidation should be a problem.
Also, as Michael suggested, Cr is a getter, so you should see the pressure
drop as the evaporation rate is increased. So run it for a few minutes
before opening the shutter.


On Fri, Oct 16, 2015 at 4:12 PM, Ali Alsaqqa  wrote:

> Thanks Andrew. Are you suggesting depositing at a higher rate to reduce the
> total time of deposition and hence time of exposition to oxygen? I would
> have thought that the higher the rate, the higher the chamber temperature
> and hence the lower the vacuum level.
>
> 2015-10-16 10:55 GMT-04:00 Andrew Sarangan :
>
> > The 10^-7 Torr during evaporation is a pretty decent vacuum level, and
> the
> > oxidation rate should be very minimal especially if you keep the
> deposition
> > rate high.
> >
> >
> >
> > On Mon, Oct 12, 2015 at 8:44 PM, Ali Alsaqqa 
> wrote:
> >
> > > Hello all,
> > >
> > > I would like to know what is the best way to prepare films of elemental
> > > Chromium. Exact thickness does not matter, but something like hundreds
> of
> > > nanometers should be fine. The target measurement is simple transport
> (I,
> > > V) in the presence of some magnetic field.
> > >
> > > My main concern here is oxidization. I was thinking about depositing
> the
> > > films using e-beam evaporator, but it can attain a vacuum of only 10-7
> > > Torr, and with this level oxidization will occur. MBE is not an option
> at
> > > the moment.
> > >
> > > I was also thinking about buying wafers from commercial sectors, but I
> > will
> > > run into the same problem, i.e. the surface will oxidize as soon as it
> > > contacts air.
> > >
> > > Are there any suggestions?
> > >
> > > Ali M. Alsaqqa,
> > > PhD candidate,
> > > Department of Physics,
> > > University at Buffalo, NY, USA
> > > _______________________________________________
> > > Hosted by the MEMS and Nanotechnology Exchange, the country's leading
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>
>
> --
> Ali M. Alsaqqa,
> PhD candidate,
> Department of Physics,
> University at Buffalo, NY, USA
> _______________________________________________
> Hosted by the MEMS and Nanotechnology Exchange, the country's leading
> provider of MEMS and Nanotechnology design and fabrication services.
> Visit us at http://www.mems-exchange.org
>
> Want to advertise to this community?  See http://www.memsnet.org
>
> To unsubscribe:
> http://mail.mems-exchange.org/mailman/listinfo/mems-talk
>
_______________________________________________
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