Tuesday, November 15, 2011

I was just trying to reply to a comment on the sputtering video and I couldn't get it to work, so this post is a bit personal!

Hi Elena!
To be honest the setup is very low-tech! The magnetron is just a "deep pot" magnet. It needs to be Alnico or Samarium-Cobalt, these do not demagnetize with the heat. The Alnico type are cheaper. So thats what I used. I got it on Ebay.
The silver target is clamped on to the bottom of the magnet by a little ring. When I turn the salad bowl over in the video, you can see the silver disk facing the camera.
I drilled a 6mm hole in the bottom of the salad bowl to hold the magnetron. Its sealed with an o-ring.
The bowl is being evacuated from below the little aluminium "table" in the video. It just blocks the view of where the outlet is!

Oh and don't mind the vacuum gauge, I was just using it as a visual guide for when I had reached the maximum vacuum of my pump/set up. The sensor to read the vacuum level is home made and not the correct one for that meter.

Let me know what bit you are interested in and I'll put up more detailed posts.


  1. Oh, thanks for replying! So your it's a very low tech setup, and
    nonetheless you could obtain a so good metallization! What
    still is not clear to me from the video, are you using a diffusion
    pump or just the Speedivac alone ?? Do you think I could attempt
    a similar job without a diffusion pump ? I have an offer for a double
    stage lab-grade vacuum pump (oil lubricating rotating vane) capable
    of 0.002 mbar (few more than 1µ if I don't go wrong), what do you
    think ? Or do I need all the way a diffusion pump also ?

  2. Hi Elena!
    I'm sorry for not getting back to you sooner. I'm not using a diffusion pump here,just the speedivac. I think I'm only getting between 200 and 100 micron.
    You can do sputtering at quite high pressures, it seems especially with noble metals which are not affected by the remaing air.
    I hope you got that pump it sounds great!
    Let me know how you are getting on.

  3. Thank you again. I missed to check here for your reply. I avoid to bother you with private emails, also because somebody else may be interested in this discussion. Since my latest post I got a Leybold Trivac D25B pump for just 700 euros which looks like new (new it would cost about 4x or 5x I think). I said "looks" because unfortunately I'm still waiting the delivery of a set of vacuum flanges and connectors to build my final chamber and to connect the Pirani gauge I also built, so I'm currently not able to measure the final vacuum I can get and to check for possible minor leakages (the raw gauge just tells zero, but I can be anywhere, in the E-1 E-2 E-3 or maybe even E-4 range...) Btw, my provisional chamber is much similar to yours, with aluminium base and a salad bowl, waiting to find around some better (taller) form of jar. From some preliminary experiments I already made with sputtering copper I get a bare metallic stain on the substrate, surrounded by yellowish and then rainbowed deposits - I assume they're some form of oxides because the current chamber IS surely leaking now, but the procedure is promising. One problem, my magnetron heats up very much and I experienced once a demagnetized neodymium magnet. Those are the only very strong magnets I have around or can buy easily. Yes, maybe silver would be less prone to oxidize, still to try. I'm currently limited to a voltage-doubled MOT (about 5KV, some hundreds mA) because I lack an higher voltage supply with sufficient current (the classic flyback plus voltage tripler gives too low current for this process). But I read on the Internet that industrial coaters usually employ voltages as low as 300V, so I don't think I really need very high voltages...

    1. That pump sounds great! Is any of you work online? I'd love to see some pictures of you experiments!
      It sounds like the copper is reacting with some gasses alright. I have very little experience with that so far.
      I'm using an 'Oil burner Ignition transformer' 8kv at 25mA as my power supply.
      My magnetron is an Alnico Deep pot magnet. I believe it is usable 250 degrees centigrade. I have not had any problems with over heating. I have only had it powered for 3 minutes at a time, with cooling time for the transformer!

  4. Hello! Here's the update :) Ops... I made a typo, I meant I BOUGHT the Pirani gauge, not I BUILT. As for today I'm still waiting connectors and pieces (unfortunately here in Italy it's not so easy to buy vacuum stuff... I had to ask help to my father and his company for ordering because they don't sell to privates but to companies only, and there're no plain or online shops here selling those goods... the usual mess :-/) The Pirani gauge is a Thyracont VD83, which connected directly to the pump inlet (badly with an oring, because I still miss the proper connectors!) indicates between 2 and 3 milliTorrs. Not bad ! When connected to my provisional chamber in a similar way, the result of course is ugly: some 10^-1 Torr, but I don't mind too much, the chamber is leaking and uses improper materials and connectors. So, my preliminary tests all felt in this very rought vacuum range. I tried with silver (not pure silver because I don't know where to find it, the scrap I used contained much copper) but there's to say that anyway the deposition is fast and pretty good the same! While I got no deposition at all with aluminium, not even oxide, and with nickel (ok, nickel is magnetic so maybe the sputtered atoms are attracted back by the magnetron) while copper requires long times/high currents and still deposits lots of oxides. Unfortunately I can't find magnets such the one you told in my neighborous, just neodymium ones, which don't tolerate too much heat. But I suspect that with a better vacuum I won't need more than some 10s mA. I alternate between different HV sources for my current experiments. I have a OBIT-alike rated for continuous work, salvaged from a fly exterminator, which gives 7KV peak at 13mA; a MOT and a 200W 230-500V trafo. I usually connect a full wave doubling-rectifying stage to the output. I'm also considering using some custom made RF supply to look for possible advantages. Oh, I don't feel so interesting to send you some photos of my preliminary works yet for the reasons above described. But I will do as soon as I can set up a better chamber with proper materials, connections and of course without leaks! You can contact me privately of course if you wish, just go to my link and you will find my email address. Bye!