I want to make CO and Si thin films. I am using 29w,30 sccm,Ar,1.8E-1 pressure.
but the plasma is not seen .
You need to find the optimal parameters to start the plasma, once started you can slighty modify then to you desired values (for this you need a shutter so you not start the deposition too soon).
1. Check that you do not have a shortcircuit between anode and cathode
2. Check that distance between anode and cathode is adequate (this depends on the pressure, for 0.018 (mbar?) with 1 mm is quite enough. But check your magnetron manual first.
3. Check that you have Argon inside (start from a low base perssure and let the gas go into the chamber). Watch out here the pumps and vacuum gauge range!
4. You probably will need a pressure shock, a Power shock or both: go first to higher pressure and higher power (0.3 mbar, 50 W, I would say)
5. Optimize your Matching box for the pressure range (you may need vary the capacitande or the inductance: check the manual of you RF source). Otherwise you reflected power would be so high that no forward power is transmitted to the plasma.
6. Check vacuum leaks, electronic contacts and, above all, check your machine manuals.
7. Once you have a beautiful pink Argon glow, send us a picture.
Good luck!
Silicon is likely to have an oxid layer. You might want to presputter at higher power and pressure with a closed shutter as already described for several minutes to get rid of Oxygen contamination.
Change power and flow stepwise towards the desired values and check if the voltage is rising fast (more than 10V/min). If so your bonding is melting and you should go a step backwards. Watch the Plasma as well while setting your values because at one point it might just turn off.
The Ar pressure you use is high. We are working at 1 x 10exp(-2) mbar. It is a 6 inch diameter target magnetron. Did you already had successful operation of your RF sputtering system? If not check the electrical components and the resistivity between the magnetron electrode and the earthed shielding of the magnetron. This should be in the higher kiloohm range. Check that the target doesn't make a short circuit there. I hope your power supply or software in the controlling computer is showing the DC bias value. This parameter is the only control parameter with physical relevance. Try lower pressure and open the shutter if there is one. In our system the plasma is only started to burn when the shutter is open. After 1 second one can close the shutter and the plasma is still there. But this could be different in your system. After you can see the plasma increase slowly the RF power and look on the resulting DC bias. You should have a DC bias higher than 70 V. Adjust the power to get the wanted deposition rate. Below 50 V there is nearly no etching on the target. Oxide layers are not critical. We deposit even SiO2 and Al2O3 from targets made of these materials.
Best regards
Dietmar Hirsch
Do you want to made cosputtering with two targets Co and Si?
Firts optimize for Co and later Si.
If you have two targets, probably in the surface of Co, you have an oxide, and you need increase the power with RF or clean the surface physically.
what type of plasma source is this? ICP or CCP? In either case, 29W at that pressure is too low to strike a discharge. If you want to get good quality thin films, you must reduce the pressure below 10^-3 mbar with gas load.
For CCP lower power is ok to start, but for ICP you need higher power to strike discharge. Please let me know what make and model of ICP you are using or send the specs of the system. We do our own ICP source for several applications. You are welcome for any kind of help.
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