Miaomin,

I have deposited high quality PECVD oxide and nitride on pure Cr and Cr/Au/Cr -

The gold layer might be your problem -
1) you might not be getting the adhesion you need to grow a good layer try
putting a Cr adhesion layer on top as well.

2) stress induced buckling might be the problem the stress is induced by the
difference in the coefficient of thermal expansion - with a ~100 nm Cr adhesion
layer this happened to several of my films at around 500 C. If your quick scan
with a profilometer has several periodic hills and valleys - this is your
problem.
Thanks,

Greg Miller
KVH Industries
Email: gmiller@kvh.com


-----Original Message-----
From: [mailto:kin@astri.org]
Sent: Tuesday, May 13, 2003 8:16 PM
To: General MEMS discussion
Subject: Re: [mems-talk] black dots on SiN


I believe the 300oC chamber ruined the Cr layer. Why don't
try to etch off the SiN and see if the dots remain there?
H3PO4 can etch SiN without etching the gold layer.


> dear colleagues
>      I have been working on a PECVD SiN 2000A dielectric
> directly on Au layer (In a new STS PECVD equip.capactive
> coupled plasma, 8" plates,temperature 300 centidegree
> ).However the film is full of uniformly scattered black
> dots 1 micron or less (film extrusion under SEM )in
> diameter. No such dots found on SiN on Silicon surface.
> Can anyone give me some explain and/or improvement advise.
> BTW,Need I deposite oxide before SiN deposition? can you
> give me a good way to pattern the SiN without affecting
> the Au/Cr beneath? ThX in advance.
>
>
> ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ÖÂ
> Àñ£¡
>
>
> ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡miaomin
>
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡miaomin@ime.pku.edu.cn
>
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡2005-05-13
>
>
>
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Best Regards,
Kin


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