If you don't find anything else, a standard aluminum etchant such as
Transene's Aluminum Etchant Type A, of course is capable of etching the
native oxide as well as the underlying aluminum.
The etch rate at 50 C is about 600 nm/min = 10 nm/s, so a dip of a few
seconds should be sufficient.
    --Kirt Williams

----- Original Message -----
From: "Wilson, Thomas" 
To: 
Sent: Friday, November 12, 2004 9:32 AM
Subject: [mems-talk] wet etching the native oxide from sputtered
aluminumthin films


> I would like to find a suitable wet etchant for the ~5-nm native oxide
> that "rapidly" grows on top of freshly sputtered aluminum upon exposure
> to air. My hope is that if the wet etch can be done within a minute of
> inserting the sample back into the sputterer loadlock (for the next
> patterning step involving deposition of Cr/Au contact pads), the native
> oxide will not have time to regrow. The sputterer that I use doesn't
> have a dry etch in-situ capability.
>
> Thomas E. Wilson