Hi,

I've taken a look at the effects of the standard HF etch performed by
MCNC/Cronos on polysilicon stress and thicknesses. It can affect the
stress state considerably, especially stres gradients, and is area
dependent. If you would like some more details, and also references to
electrochemistry, you can look at my thesis at
http://www-tcad.stanford.edu/~chan

Best wishes,

Edward Chan
Bell Laboratories
Wireless Components Research

On Mon, 31 Jan 2000 michael.pedersen@knowlesinc.com wrote:

>      The electrochemical potential caused be the metal/semiconductor
>      interface may lead very slight etching/dissolution of the polysilicon
>      in HF.
>
>      You could try to release the structures in a lower concentration HF.
>
>      Michael Pedersen
>      Knowles Electronics
>
>
> ______________________________ Reply Separator
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> Subject: No subject given
> Author:  "Glen Smith"   mems-cc@ISI.EDU at
> -INTERNET-MAIL
> Date:    01/28/2000 1:16 AM
>
>
>
> In the presence of chrome/gold, discoloration of the polysilicon layers is
> seen when releasing the MUMPS devices in 49% HF.
>
> Anyone out there with an explaination and a possible solution?
>
> Thanks
>
> Glen
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