Hi folks,

I defined a gold pattern by e-beam lithography and lift-off. The gold was
evaporated on the SOI with ~8nm Cr as the adhesion. After several other
fabrications (mainly DRIE), I had some free-standing gold structures sitting
on a silicon structure made by the device layer of a SOI wafer. My last step
was to release the whole structure by HF etching the buried oxide layer. I
used 49% HF for 3min to achieve the necessary undercutting to make sure my
structure was free. However part of the gold structure was peeled off.

How can I improve it? Is there another adhesion layer that can resist HF
better? I tried BOE instead of 49% HF. It didn't help much.

Thanks a lot.

Jay