Maybe a leak in your system?  If the aluminum were reacting with oxygen
on its way to the wafer you would get aluminum oxide, which is white.
In any case, do a composition analysis if you can.


Sachin Rane wrote:

> Hi,
> I have been trying to make ~ 1-2 micron thick aluminum films by
> thermal evaporation. The films I get are typically white in color
> (non-shiny) and rough (inspected through AFM). I have used both the
> boron nitride crucible and tungsten boat as the source. The pressure
> at evaporation is typically 2*10^-6 (before starting evaporation it is
> < 10^-6 ) What is the problem? Or is thermal evaporation not a good
> method for this?
> Thanks
> SR
>