Hi Udaya,

If you only have a rorary pump you will ahve high background O2 and H2O pressure. Just put a cold trap between your pump and vacuum system and fill it with LN2. It will increase your pumping speed and lower the partial pressures of H2O, CO2, CO, etc.

And you don't need such low partial pressures of O2 since you're sputtering oxides which need a supply of O2.

Hi Udaya,

If you only have a rorary pump you will ahve high background O2 and H2O pressure. Just put a cold trap between your pump and vacuum system and fill it with LN2. It will increase your pumping speed and lower the partial pressures of H2O, CO2, CO, etc.

And you don't need such low partial pressures of O2 since you're sputtering oxides which need a supply of O2.

In principle you can di sputtering with only a rotary pump, however your films will not be as clean as films produced at low vacuum conditions.

To improve vacuum you could try to use an LN2 trap as already suggested. Of course this is reasonable only if you have one hanging around, otherwise you should better spend your money in an used diffusion/turbo pump. Other ideas are listed below in order of increasing cost.

1. You can use the strong affinity of Zr for oxygen to reduce residual gases (e.g. water and oxygen) in the vacuum chamber. To deposit ZrO2 you first (pre-)sputter Zr for say 10-20 minutes while keeping the substrate covered by a shutter, and only after that you perform the real film deposition in a more controlled oxygen atmosphere. This presputtering stage not only cleans the surface of the Zr target (you should always do presputtering before any film deposition!) but to a certain extent also removes water and oxygen molecules from your cvacuum chamber. To deposit Al2O3, you first (pre-)sputter Zr for say 10-20 minutes, then presputter the Al target and only at the end you deposit the film.

2. You can bake out the walls of the vacuum chamber, provided that you have the proper heating tapes [see here for an example: http://www.mdcvacuum.com/displayproductcontent.aspx?d=MDC&p=m.a.1.1.1] or heating jackets [http://heatingtapes.com/collections/jackets-blankets] (if you already have some in the lab, pay attention that old models contained asbestos!).

3. You can use a Ti sublimation pump (https://en.wikipedia.org/wiki/Titanium_sublimation_pump), which again uses the affinity of Ti to improve vacuum conditions in your sputtering chamber.

I second what Sabino said. Otherwise the quality of your films will be much much lower. Also you need to consider the throw distance in your set-up as for higher pressure sputtering the mean free path of sputtered species will be quite low, so try to minimize target to sub distance. Good luck!

For all purposes yes. Since you will a sputter gas at a relatively high pressure, a starting vac of 10-6 torr is OK. If necessary for metallicfilms you may sputter a Zr sheet fo a few minutes which would absorb the residual oxygen; In any case how pure is your sputter gas (Ar)? If it is 100ppm or so then nothing to worry;

contamination will be your problem. a cold-trap is advised to hod back oil vapor (hydrocarbons) from your pump (if you can afford use PFPE kind of oil). Flush 5 to 10 times your reactor to dilute your rest nitrogen, water, carbon dioxide gases. Find out the right pressure and sample-to-cathode distance, depending on self-bias voltage. nothing is impossible, good luck.

While the answer to the question is YES, the underlying question should be, will anything good become of it? Unless you know that the vacuum system is leak tight, by analysis with a residual gas analyzer or similar diagnostics, you may have high partial pressures of N2 and hydrocarbons. Both of which can react with the target material to form Nitrides and Carbides. Having said this, and given the limited resources for vacuum improvement, I would say take a shot at deposition...and have the film produced analyzed to insure you are not depositing other materials than Al2O3 and ZrO2.