If you have a sputter gun in your vacuum chamber, or an arrangement for a dc diode sputtering.

Try to sputter Ti target for some time. The deposited Ti films will absorb oxygen, because of the all the elements Titanium has tremendous solubiulity for oxygen, and loves oxygen. You will see a tremendous improvement in vacuum level, soon after Titanium sputtering.

K. Sreenivas

First we can fill it with N2 or CO2 then evacuate the chamber, this just reduces the amount of oxygen but not completely remove

Thank you for your reply Mr. Prakash. I know it, we can reduce the amount of oxygen by noble gas and nitogen but this process actually doesn't eradicate oxygen and moisture properly. I am looking for a better method to remove most of the oxygens

Removing oxygen is very important with many silicon processes. Ultrahigh vacuum, long bake-outs, and possibly a getter, or a cryopump to get down to 10^-11/-12 Torr.

Here are some references:

http://lpc1.clpccd.cc.ca.us/lpc/tswain/chapt3.pdf

http://www.oxford-instruments.com/products/cryogenic-environments/cryo-pumps

http://tinyurl.com/pcmxcwt

Practically, it is never possible to make completely O2 free environment, current pumping systems reaches upto 10^-11/12 torr. still it has O2 content...But I think for most of metals it is good enough...

@Naveen - except the vacuum is 10^-8 atmospheres = 10^-5 Torr!

So this is a simple vacuum from perhaps a scroll pump.

It is better to flush the chamber two-three times with inert gases such as Argon. So that it can minimize oxygen and other contaminating gases from chamber. It is not possible to remove all the oxygen content from chamber, but flushing with inert gases would provide you good environment for using synthesis of metals particles.

Once at 10-7 torr, start a two-three days baket out of whole chamber; minimum temperature 105 C; can go higher as long as the instruments /materials used in your chamber can cope.

I routiney maintain UHV chambers at 10^-9 to 10^-11 mbar with zero oxygen. Normally if you see oxygen at 10^-8mbar you have an air leak into your system, small but there. You need to leak test the system. As mentioned above, you also need to bake your system ,, but usually this is to get rid of water mostly. Also are you sure its 10^-8 atm? that doesnt sound right, most pressure units for vacuum systems are measured in mbar or torr

Does your UHV system use ISO flanges or CF-flanges (with copper rings)? You have to make sure the rings are of good quality as well as the condition. With ISO flanges you have to check the type of sealing rubber/gasket used. Additionally, your backing pump can not give sufficient backing vacuum resulting in high load on your turbo pump.

10^-8 atmospheres ~= 10^-5 Torr ... his vacuum chamber is NOT UHV!

@ Peter yes, agreed !unless 10^-8 atm is a mistake in the units it is a strange unit to use for a vacuum system....

You could first purge the system with N2 gas and also heat the chamber while pumping.

Also, you could evaporate a metal in the chamber such as Al to react with the O2.

also,when you bring the system back up atm use N2 gas because the O2 will adsorb to the metal when you crash the system to air. it can take days and baking to get the O2 out if you dont use N2 gas to bleed up. You could also add a cryopump to the system to freeze it out. Hope these help.

Have you ever thought of using a titanium sublimation pump? http://en.wikipedia.org/wiki/Titanium_sublimation_pump

Zirox VAK is a potentiostatic oxygen sensor ready to use in vacuum system (frange 40 mm) (zirox company in Germany - cheap, 2-4 ke, or you can make it yourself if you have some time). It is based on zirconia doped ceramic operating at 750°C really locally, using the outside air as reference. The Inside gas, which is to be measured, is in contact with the electrode covered with platinum. With such a system, you will follow the actual oxygen content of the vaccumm chambers, especially during gas purging and heating procedure.

To reduce further on the oxygen : playing with oxidation of metals is an easy solution, such as Al method of Preston. Sodium, or other as well. Some fresh sodium surface will do the job if you put a small cup at 110°C, the equilibrium partial pressure is something really low (10e-60 bars so long I remember), and the kinetic of oxidation pretty fast. Some other methods simply use the oxidation of an excess of iron metal (ships) in an oven (600°C or so) set in the inlet gas system.

Hope this can help.

jlouis

What method of deposition are you using? A long slow preheat prior to deposition would be beneficial for thermal evaporation deposition (either through resistance or e-beam). This may help improve the quality of the film a bit. 

Regardless of small things, it seems that you have inadequate pumping to keep up with the leak rate of your system. If you are in the 10^-5 Torr range, even if you use a Ti sublimation pump your leak rate will overwhelm the advantage quickly. 

What type of pump set-up are you using? How old are all of your seals? 

A hard seal (CF) chamber, pumped with a cryogenic pump, and allowing for a long high temperature bake out are the best bet. 

Thank you very much all for all your replies. I am really grateful to you all. 

At the beginning of my masters, i was actually trying to fabricate nanospheres of Sodium, but after, it didn;t look like a realistic project. So, I switched to something else. 

However, thanks all of you very much for being so much helpful to me. 

If you have a sputter gun in your vacuum chamber, or an arrangement for a dc diode sputtering.

Try to sputter Ti target for some time. The deposited Ti films will absorb oxygen, because of the all the elements Titanium has tremendous solubiulity for oxygen, and loves oxygen. You will see a tremendous improvement in vacuum level, soon after Titanium sputtering.

K. Sreenivas

Dear Professor K. Sreenivas,

Thank you very much for your very helpful comment.