Hi all.

I'd like to design a chip with a very crude resistance thermometer on it
(as well as lots of things that do wildly exciting science).  Using
optical lithography and thermal evaporation, and I'd connect by
overlaying Cr/Au bond pads.

It occurs to me that someone on the list must have done it before.

Any tips on metal system, or technical pitfalls that I should know about?

Nichrome makes a good resistor, but has poor temperature co-efficient,
whereas Au, Al, Cu, Ag etc are horribly good conductors, but vary
nicely.  I'd rather keep away from toxic or otherwise difficult metals
(W, Zn, Ni, Fe etc) as I'm giving it to students as a project.

It can be pretty crude accuracy-wise.  I'd be delighted with +/-5K at
nitrogen temps, and it's a simple two-terminal resistance measurement
such that the resistance is dominated by the thermometer.

I'm not interested in separate sensors, just on-chip resistance.

All tips gratefully received!

Andy