Hello,
I'm developing a recipe for deep Si etch
using a Cl2 based ICP process. After some
time the surface of the exposed parts of the
silicon wafer that I'm etching, becomes black.
Has anyone had the same problem? I'm trying to
avoid it but I can't since I don't know what
it's due to.
Before etching I make a short HF dip to clear off
the native oxide and I use only Cl2 gas.
The surface doesn't look very much rough, so it is not
a black silicon type of thing.
Thank you for the attention

Best Regards
Matteo