It is unlikely the paper will burn, as the pressure in the system during sputter deposition is not high enough to ignite the paper. Obviously oxygen ions and radicals will modify the surface of the paper and graphite until it is covered with a thin film of silicon dioxide. Just to be on the safe side, keep the power low and maximize the distance between sputter source and substrate.

Ignition temperature of paper is around 180 oC at atmospheric pressure. This temperature is going to be lower at lower pressures. Be sure, that your substrates do not exceed 180 oC and everything should be fine. Substrate holder cooling and temperature measurement at substrate during the sputtering will be very useful.

Hi Farha,

There is practically no oxygen present in the vacuum environment when you sputter an oxide, providing you use a compound oxide target (SiO2 and Ar gas) and don't do reactive sputtering with oxygen (e.g. O2-Ar gas on a Si target). For that reason you don't have to worry about ignition. During sputtering the substrate will heat up because of hot electrons hitting the paper and condensation energy from the SiO2. In sputtering these temperatures can become really high (300-400 C, depending on the thickness of the deposited layer and when the thermal mass of the substrate is low (as in your case). It was suggested that you have to cool the substrate table with water but that will not work since heat conduction in vacuum is practically nill. The best thing to do is to give your paper more thermal mass by glueing it on a piece of ceramic or metal. Alternatively you can stick the paper on a piece of metal with vacuum grease which also works really well to keep the temperatures down and might help that the paper does not shrink or shrivel. After sputtering the paper can then easily be removed from the metal baseplate.

We have experienced the following while sputtering some other oxide coating on paper by sputtering technique.

1) It depends on the paper to a great extent.

2) Sputtering conditons (especially pressure) and substrate to target distance.

     If the pressure is high then it is good.  However at low sputtering pressure 

      ion bombardment effects onto the substrate (paper) can damage the paper.

      One should put the paper substrate at an appropriate distance from the target.  

3)  We tried different kinds of paper for oxide coating.

      Normal tissue paper (very porous), whatman filter paper  and butter paper

      were found to get damaged.

4)  However notmal A4 ppaper, and credit card thickness paper sheets were found to tolerate the sputtering conditions slightly better.

this is a very interesting field of research, and experimental observations are just coming up in the reported literature.

K. Sreenivas