> It has been reported that gold black, silver black, aluminum black can be
> used for this purpose but I wonder whether they can adhere strongly to
> the passivation layer above the thermocouple and be patterned.
> Any construction method or reference advice will be highly appreciated.

I don't know about the suitability of these as absorbing layers,
but can comment on processing.

Only about three commonly used metals adhere well to
silicon, silicon dioxide, and silicon nitride:
aluminum, chromium, and titanium,
(all of which are readily oxidized).

Cr, Ti, and also Ti/W alloy,
in thicknesses of 10-100 nm,
are commonly used as adhesion layers.

For patterning, many people use lift off of photoresist
so that no etching is needed.

I've successfully done this with Cr  under Au.

If the stress state of the films are unknown
and thick films are not required,
it is best to keep them the top film thin (say 0.1-0.3 um)
to avoid peeling.

******************************************
Kirt R. Williams, Ph.D.
Research Staff Scientist
Lucas NovaSensor
1055 Mission Ct., Fremont, CA  94539-8203
Kirt_Williams@compuserve.com
(510) 661-6147  FAX (510) 770-0645
******************************************