Aluminum has already a 10 nm of a natural oxide layer if your film is exposed to air. What is your film thickness?

You can use some acids to get thicker alumina layer. Just search in the liturature

My film thickness is 150 nm and it is exposed to air. I want to convert the total film as aluminium oxide Mr. Civan Avci. 

You just need to anneal your film in air for a certain time at a certain temperature. (I am not an expert but, may be to start, try 5h @300 oC) 

However, for a more homogenous and stoichiometric Al2O3, I would suggest you wet chemistry. For instance, I would coat my substrate with an aluminum butoxide solution by dipping or spin coating, and burn the film in air. In this case you will have 100% Al2O3 for sure. With the spin speed and the concentration of your initial solution, you can adjust your film thickness. 

Thank you Mr. Civan Avci.

Heat treatment in oxygen environment would give you the desired result. However, stoichiometry depends on the oxygen pressure. Vary it to get near stoichiometric composition.

Anodizing can convert Al to Al2O3, however you non-conducting glass substrate could cause problems.

Hi,

Anodozing is a reliable metohot. Sulfuric acid, phosphoric acid or cromic acid anodizing is possible.

The film can be extracted by using mercury iodine to remove remaining Al and stored in alcohol.

Best wishes

Sten

by anodizing process. Al must be anode to dissolution and then convert to aluminum oxide. Can you use acidic electrolyte with certain conditions. 

Why not deposit Al2O3 instead of the Al. Just add O2 while you are evaporating the Al. Varying the O2 will be needed for optimal parameters.

Otherwise, trying baking Al in oven at 300 C for 24 hours with an O2 backfill.

you can use aluminium target in argon and oxygen atmosphere in any mode of magnetron sputtering (RF / DC / pulsed DC). you have to optimize the growing condition to get stoichiometric film.

It would be much more easier introducing O2 into your evaporation process, then to try baking Al film at 300C in an O2 atmosphere if you are using thermal or electron beam evaporation. If you are sputtering by magnetron use 3-1 ratio, Ar-O2, there maybe arcing occurring at target surface.

Evaporate at about 1-2 angstroms per second with a partial pressure of O2 at 2 x 10-4 torr.

Could I totally convert the 10nm Al to Al2O3 in dry air?

In my case, I want to generate 10nm layer film of Al2O3 by RF sputtering using Al2O3 target. Could you give me some sound advice?

anodie the film with with acids