Few days back, I deposited Zn film on glass using e-beam evaporation and it was successfully deposited. The vaccum was about 3x10^-6 mbar with diffusion pump. Today, when I turn on the system I could not get high vaccum. The penning gauge is not responding and it stuck to ^-3 mbar. All appears to be okay, I just could not figure out the problem. You suggestions are highly appreciate.
Hi,
Generally, low melting point metals like Zn, Sn are dirty as far as e-beam is concerned as they contaminate the chamber heavily. They are better deposited in a thermal evaporator. If your vacuum gauge is at a line-of-sight location w.r.t. your source, there is high chances that its active component is choked. You may have to degas the vacuum gauge. You also observe the load on the pump (like normal operating power, current, etc). This will show higher values if there is an outgassing source in the chamber. If this values are normal, gauge is the culprit.
Regards
Thanks everyone for the suggestions. Zinc dust was deposited in the gauge electrode.After cleaning the penning gauge, we could bring the system operational. Now, the chamber is at vacuum of 9x10^-7 mbar.
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