Possibly, one could try direct metal sputtering in oxygen mixed Ar plasma created during sputtering under dc conditions. RF sputtering is extremely good for dielectric depositions but VO2 being different in behavior may not be conducive for converting from V2O5 into VO2. Perhaps it needs a number of trials. However, the quality of target, impurity in Ar and the pressure used - all these conditions are equally important for controlling the quality of the deposits.

If you could get a VO2 traget that would be best. You can then sputter with RF and get almost stoichiometirc VO2, maybe including a little O2 to the Ar flow to compensate for O2 loss. You can also use a V target but then you have to figure out the exact regime (O2 in Ar) in which you poison the target to the extent that you deposit VO2. This last method will be more challenging since you easily form V2O5.

Adding to my previous amswer you could deposit V2O5 and try to reduce the layer in an anealing oven at the proper Po2 pressure to form the VO2 phase. Also rapid thermal annealing in a reducing atmosphere with the right Po2 could be used to create VO2.

I do agree with the answers given by Peter Knapen. Sputtering being in an energetic reaction regime, it affects every surface that comes in contact. On the other hand, it needs enough experimentation to find out the exact partial pressure of oxygen to get the stoichiometry. So the easiest solution is to get good quality VO2 source and sputter using RF energy with some compensation for loss of oxygen if necessary.

I recommend VO2 and deposite at the O2 plasma ambient

Hi Rama Satya Sandilya, I would suggest reactive pulsed DC sputtering of a V target (with oxgen). Though you would need some post analysis to help tune your set up to ensure you preferentially produced VO2.

I would always opt for using a metal target where ever possible, as it is cheaper to buy and does not require RF sputtering which is always very inefficient and slow.

If you are doing PLD, buy Vo2 powders, make a dense target and use it, have the right substrate temp. and oxygen pressure.

If you are doing sputtering, prefer RF sputtering, you can use a Vanadium metal foil, and do reactive sputtering in Ar+O2, or pure oxygen, and like to ahieve insitu crystallinity, then introduce appropriate substrate temperature.

K. Sreenivas

The suggestions given by K Sreenivas are very practical.

Thank you all for your kind answers. :)

Depending on the purity you need in your material, this may help choose your target. If you are making a target, then VO2 powders are often less pure than V2O5 or V. Furthermore, when you are sintering your target (often done in air) it can be difficult to control your oxidation state of V while getting to sufficiently high sintering temperature. As such people often prefer to make PLD VO2 films from V2O5 targets (grown at relatively low oxygen pressure) 3-5 mTorr (for our set up), or with a Vanadium target at higher background oxygen pressure.

If you're not making your own targets then vanadium targets can be purchased for around $150 and V2O5 for around $350 (www.pldtargets.com).

If you are still struggling to get the right phase, then you might want to look at matching the substrate also. VO2 grows nicely on sapphire and this may help direct your grown. This will depend on you application though and what experiments you are planning with your films.

Good luck!