Deposition of Magnesium

Magnesium is a relatively volatile metal and we have never deposited it here at Nanolab. Because of its high vapor pressure it is not well suited for deposition in multi-user systems as it will easily re-evaporate from the chamber surfaces and contaminate the films of subsequent users. We are also concerned about deposition of Mg in a chamber with a cryo pump as a very volatile metal may clog the pump.

If you wish to deposit magnesium, please explore options with collaborators at other institutions.

Below is a summary of information compiled Spring 2020 when we considered depositing Mg at Nanolab.

Summary Mg advice spring 2020

Input collected by Rebecca (reet)

None of the groups we wrote to have mentioned that they have experience with using the chamber for something else after using it for Mg.
At Penn State they used a cryo pump with Mg e-beam evaporation for many experiments (at least 2 students and several papers) apparently without issues with the pump.

Input from Barbara Shaw, Penn State University (e-beam evaporation of Mg)

Best w dedicated system for Mg, the Nanofab lab at Penn State doesn’t allow Mg.
Recommend major cleaning prior to Mg, predeposit a bunch of Mg. Major clean afterwards and predeposit next material too. Sounds like their system hasn’t been used for other stuff after Mg, so no experience with that.
They had no issues w Mg and their cryo pump as far as she knows.

Michael Störmer, Helmholtz-Zentrum Geesthacht Zentrum für Material- und Küstenforschung (sputter deposition and also cathode arc and ion beam sputtering of Mg in the past)

Mg challenging, different to other metals. Oxidizes easily - think about the environment for the prepared films.
On cross-contamination: You see the effect of Mg on the base pressure, as you do for Ti coatings, Michael doesn’t think it’s a long-lasting effect. But - don’t underestimate cleanliness.
It is possible to contact them and visit their lab. They have a lot of expertise on Mg.

Diederik Depla, Ghent University (sputtering including HiPIMS of Mg)

Mainly used their setup for Mg, haven’t checked cross-contamination.
Believes that Mg on vent will turn into MgO (stable/low-sputter-yield) which should not be a big problem in terms of contamination
They used a turbo/rotary vane pump, no specific reason.
Mg sputters easily, easy to handle targets compared to Ca and Li (sic!). During non-reactive sputtering, MgO will form on target but Mg sputters so fast it’s not a big issue.