It wouldbe grateful if you can help figure out my issue.
I am currently working on OLED vapor deposition. I am making inverted top emitting OLED. We have 3 materials to be deposited: Al, Ag and Li. All of 3 materials have to be put into the boats. but the problem is we just have 2 boats. So I plan to do like this:
Firstly I deposit Li and then transfer the incomplete device from Vaccuum chamber ( vacuum pressure 10(-6) Torr) to load lock chamber ( 10 (-2) Torr) located in Nitrogen box.
Then, I vent vacuum chamber to change material: take out Li and put Al instead ( one boat is already occupied by Ag) and then vacuum again.
VACUUM PROCESS TAKES ABOUT 1 AND HALF HOUR.
When vacuum process finish, I transfer incomplete device back to vacuum chamber and continue to deposit the remaining layers.
Is it considered as making device with breaking vacuum?
What will happen if I do like above method?
Hi Na Le,
in my opinion it would be better if you did not interrupt the deposition process with a bare Li-layer, as the Li-layer would be the most reactive one in your stack. Therefore, any impurities, trace oxygen or moisture in your load lock chamber is most likely going to react with the exposed Li-layer.
If I am not mistaken, it should be possible for you to first evaporate Li and the next metal layer (Al in your case?). At least then the Li would be covered by the second layer and hopefully that would reduce degradation during the interruption, although the Al- or Ag-layer could also react with trace oxygen etc.
However, I cannot promise you anything, you will have to play around to find the best solution.
Hope this helps.
Hi N. T. L. I agree with Joachim Vollbrecht , on the other hand, if Li-layer is not exposed, you could use Argon as inert atmosphere.
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