Hi researchers,

I have adhesion problems of evaporated Au (150 nm) to PECVD SiN (300
degC, 1 um). I'm using a Cr (50 nm) layer as adhesion. Both
evaporation processes (Cr+Au) are done in the same machine together.
I don't use any surface treatment of the SiN before the evaporation.
After exposure of the structures to O2 plasma (1000 W, 100 mTorr, 700
sccm O2) for 15 min, the Cr/Au layer is pealing off. The temperature
during the O2 plasma  etch is between 150 and 200 degC.

Questions:
(1) is the off-pealing caused by the temperature during O2 treatment,
due to stress?
(2) how can I improve the adhesion? What kind of surface preparation
of the SiN do you recommend before the evaporation of Cr/Au (like O2
plasma ...)?

Thanks very very very much for any comment,

Joachim Oberhammer/KTH Stockholm.
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Joachim Oberhammer, Dipl.-Ing.

Royal Institute of Technology (KTH)   Phone:    +46/(0)8 790 6250
Dept. of Signals, Sensors and Systems Fax:      +46/(0)8 10 0858
Microsystem Technology (MST)          Mobile:   +46/(0)70 692 1858
                                       e-mail:   joachim.oberhammer@s3.kth.se
Osquldas väg 10                       homepage: http://www.s3.kth.se/mst/
SE-100 44 Stockholm, Sweden