I have soda lime glass slides (75x50x1mm) with a Ti-Pt thin film sputtered onto it (Ti-2nm, Pt-200nm). I want to anneal it for long term stability and reduction in resistance of the Pt layer. The protocol I am following says to use 500C for 12 hours in a nitrogen purge flow.
My question is, is the 12 hour time duration absolutely necessary? A quick literature survey shows no further change in properties after 2 hours of annealing at varying temperatures. Also is the nitrogen purge flow absolutely necessary? I am guessing it is to prevent oxidation, but does it matter at low temperatures?
You may not need continues flow of nitrogen, as you said you need to avoid oxidation so purge the chamber for fee time with nitrogen keep the required pressure. Sometime, we need to post anneal our oxide thin films. For that purpose, we completely close the pumping valve and and fill the chamber with O2 at certain required pressure.
Time can be critical that what you need to check.
I agree with the answer by Mr. Anwar but you need to have a sealed pack chamber in order to avoid any air entering into it. In addition, generally 1 or 2 hours are enough for the annealing process, also keep in mind to control the heating/cooling rate, the rate should be small, as higher heating/cooling rate can result in different micro-structure.
Another way to get reduced resistance is to heat under H2-N2 mixture, this can further reduce the resistance of your material.
There must be a scientific reason when the protocol mentions annealing at 500 C for 12 hours in a nitrogen purge. Most of the times, mathematical relationships between annealing temperature and annealing time determine the parameters for specific metals. We should trust more to physics and mathematics-based evidence rather than a general opinion about them.
- Conrad
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