hi, be sure you have no short-cut somewhere..

before closing your vacuum chamber, check the the conductivity between cathode (sputtering material) and chamber wall or anode. Infinite resistance should be shown (use a conventional ohmmeter/voltmeter, may be disconnect the power supply plug).

it is easy to make mistakes when fixing the anode ring and the distance cathode-anode is not well set, too big or too small.. 2 mm should be fine.

lukas

Thank you Lukas

We have already cheked all these points, and many others!!!

Something i wander:

does the anode of the magnetron device must be isolated frome the chamber???

Is the Whole chamber must be grounded?

because actually they are, and it's not easy to change this as shown in the figures (attched file)

Kind regards

your cathode (co-axial connection form DC PS) should be isolated from ground, while your anode will be grounded. Since the connectors from the PS go on the magnetron, it is not necessary to ground the chamber, provided your PS is properly connected.

So first I would check the cathode/target without the anode shield and with the cable from the PS disconnected. Just use a multimeter with one end on the cathode/target and the other on the chamber. If this is at ground and if there is no flake between cathode base and anode, this may indicate a shortcut inside your source. I haven't personally worked with these sources, so I don't know how they isolate the coaxial cable and the target from the ground.

did you check the conductivity of your water cooling? if too high you may have current leakage via this way..  ( how big is your short-cut?  may be it is OK to have some current leakage, you may loose some real voltage on your target and have dificulties to ignite..  go ahead increase voltage if the current you have is not excessiv)

chamber and anode can be separated, but be sure the anode connection goes to ground somewhere and has the current carrying capability you need. (DC)

good luck..

Hi Lukas,

I do not think water conductivity is the problem

for groundind the anode, do you think it's efficient to do as shown in the figures attached??

Actually, i want to disconnect the depostion chamber from ground, but the safest way!!!

Thank you

hi, disconnecting your chamber from ground  you will elevate it to the plasma potential,  so if also your sample is there, you will not have the usual ion bombardement energy to your sample.. (it will less by this plasma potential which may be not that much, but in some special cases it may have its importance, you are doing semi materials, so it will probably be for you).

I think you can do like on your drawing.  But yes be sure this is safe, because not usual.  I would recommend  to isolate your sample holder instead of the whole chamber, for security reasons, but if you really need that, be careful.

now the non ignition may be due to your SiC target. I have no experience with this kind of targets. how conductive are they?  but shouldn't non-conductive targets produce arcing with a DC PS? or the charging capacity is too low for that? an may have problem igniting, and the current you see is some leakage through water or the semi-conductor SiC?  

how big is the current you see without plasma? for which voltage/pressure..

10-2 mbar for pressure,6sscm Ar flow rate:  12 V 25 mA......24V 49 mA  usually, plasma (and current) appear at -350V to -400 V

hi,  you mean +12V ?  but it is definitively not a short-cut..    or if it is then via the SiC target which is not a good conductor.    Sure it is not related to your cooling agent?

This current is not dependent on the pressure you have? even in air you would have it?

ca marche maintenant ?

Bonjour! On peut écrire en français dans ce site !!!?

Actually, there was a water leak inside the magnetron cathode, because of a fissure in a wall Teflon, which should have never crack. Something crazy !!!

yukatta..  so the things are cleared..

viel spass..