Hi mems-talk,

I purchased some thin SOI recently to make some fixed-fixed beams and
cantilevers, and I was assuming that the device layer would be close to
zero stress (slightly tensile, if anything) and have no stress
gradients. Having made the structures, it seems that the device layer is
compressively stressed (the fixed-fixed beams buckle) and has a stress
gradient (the cantilevers curl upwards). I was wondering if anyone has
tried to anneal SOI wafers to reduce stress and/or stress gradients, and
if so, what conditions did you use?

The SOI has a 260nm thick device layer and 2000nm thick oxide layer, if
that helps.

Regards
Jason Milne
The University of Western Australia
Microelectronics Research Group