I spent 7 years in the LCD industry doing just this so can vouch for the method which was honed after a number of years.  Keep finger marks off the coating or edges of the substrate!

Sonicate for 15 minutes in a warm (50 - 60 C), 5% non-phosphate surfactant (e.g. Decon 90). Rinse for 30 minutes or so in flowing filtered DI (18 megohm) water for 30 minutes.  This surfactant solution is made up in filtered (0.02 um) DI water.  Allow the substrates to run dry in air - the water should remove as a film and not 'blobby' on the surface.  This simple method worked well and by observation it was easy to see if the system was clean - filtered DI water is essential.  All this was relatively easy to achieve on an LCD production line.

Have you considered to smoothen the ITO substrates in an O2 plasma?

I use this technique as a standard preparation step before using the substrates for thermal vapour deposition. Although I am not sure, if this will help in your case.

ITO surface is not so smooth depending on the coating technique on a glass substrate.

If you want, you can consider etching the surface with a really weak acid for maximum 1 munite. By that way you can make the ITO surface little bit better.

And then you can find the general cleaning process of the ITO substrates for optoelectronic applications at literature, which is putting the substrates into acetone and isopropanol (and the third step as water, depending on your application) respectively and clean them in the ultrasonic bath.

After that step you can consider using UV-ozone treathment or O2 plasma for better cleaning.

Good Luck...

The thermophoresis force (temperature gradient between surrounding and sample (higher temperature than surrounding)) has been used to set in by providing an appropriate temperature gradient of the laser exposed surface, sampling for microscopy and other application.

Do you have possibility to increase samples temperature in order to avoid particle deposition in surface of your sample?

I have found this paper. You can take a look on it.

Eung Suok Lee,Jai Hyuk Choi and Hong Koo Baik, Surface cleaning of indium tin oxide by atmospheric air plasma treatment with the steady-state airflow for organic light emitting diodes, Surface and Coatings Technology, Volume 201, Issues 9–11, 26 February 2007, Pages 4973–4978. doi:10.1016/j.surfcoat.2006.07.202.

Best of Luck.

ITO glasses can be cleaned by sonicating for 30 minutes, first in acetone then in isopropyl alcohol (IPA).

The samples can be placed in UV-ozone (UVO-Cleaner) to remove any residual organic contamination and to increase hydroxyl moiety concentration by surface oxidation (if desired).

It is important to remove organic solvent that has been used during cleaning procedure (for example by a proper treatment in a vacuum oven).

After cleaning, the samples have to store in an evacuated desiccator until use.

How thick is your ITO? Is this the first step in your process or are there residues from prior steps you're trying to eliminate as well? IIRC it's pretty hard to get really smooth ITO as it's generally polycrystalline in most deposition methods (Nod to Nurhan, here). It's even worse if you have a high temperature step in your process flow.

I'm with the consensus. Sonicate acetone, isopropanol, deionized water for cleaning. UVO, if possible, is a good step.

HCl and aqua regia will etch ITO, so that'd be one possible method to smooth out the surface. Low concentration, as it etches pretty fast, and I worry about it attacking grain boundaries. You can also put it in a RIE and "tickle" it with a Ar/O2 feed at low power. That will smooth out the high spots and hopefully remove any last residue.

My old process flow for ITO coated glass (Delta, 180 nm on Corning 1737) was: 1.) 45-60 minutes sonication in 45 C Contrad 70 solution. It's gentle and should release a lot of the junk.

2.) Rinse DI to get any last detergent, then acetone, IPA, DI (all spray bottle).

3.) I used to leave it at least 30 minutes in our 125 C dehydration ovens

4.) Spin Shipley 1818 for patterning.

Thanks Daniel for your advice. I actually bought it from Delta tech as well. Thickness is around 25 nm and I use it as a conductive layer for e beam lithography. But my structures get bad because of the uncleaned substrate ( SEMs attached) . I do sonication in acetone, IPA and rinse it with DI and get the SEM images attached. So, I will try the contrad 70 and O2 plasma to see if it improves the surface morphology.

Mehra, I will try to do a bake as well to see if it improves.

Thanks All for the suggestions. If I get something better, I will post it.

Abdul--that looks a lot like grain morphology and not "grunge". What's the substrate? At 25nm thick you could be getting a lot of the underlying morphology coming through, too.

Can you cleave and get a cross section? With 25nm thick, you may need to go to TEM unless your SEM has a killer HR lens.

Daniel--I will do the cross section and see how it looks. Thanks again

Sonication in appropriate solvents...

Hi guys,

I've been trying to drop cast carbon nanotube (dissolved in water) on ITO. I'm struggling to find the best cleaning conditions to clean the cast. Also does anyone have an idea of how long I should cast the surface for?

Thank you

Hi guys,

I have a 5-10 nm ITO layer on top of my glass. Is it possible to do this procedure to clean it? I am worried if I will destroy the layer by acid or etc.

Thanks a lot,

Sajjad

Dear Sajjad,

You can try the cleaning methods based on your ITO sheet resistance as listed in the attached paper. I ever tried the cleaning protocol by 30 mins of sonication in DI water, acetone, IPA and DI water, respectively, then blow it with N2 gun to dry, followed by O2 plasma treatment for 30 mins. In my case, my substrate could immobilize PS nanobeads uniformly with great monolayerity. My sample sheet resistance was 7 Ω/square.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.464.7179&rep=rep1&type=pdf

I spent 7 years in the LCD industry doing just this so can vouch for the method which was honed after a number of years.  Keep finger marks off the coating or edges of the substrate!

Sonicate for 15 minutes in a warm (50 - 60 C), 5% non-phosphate surfactant (e.g. Decon 90). Rinse for 30 minutes or so in flowing filtered DI (18 megohm) water for 30 minutes.  This surfactant solution is made up in filtered (0.02 um) DI water.  Allow the substrates to run dry in air - the water should remove as a film and not 'blobby' on the surface.  This simple method worked well and by observation it was easy to see if the system was clean - filtered DI water is essential.  All this was relatively easy to achieve on an LCD production line.

After etching of ITO , i have cleaned ITO coated glass in proper way but i am not able to seen patterned portion of ITO. what is the reason

@ Debarati  have you etched off all the ITO?  Easy to do....

Agnes Purwidyantri Thanks so much!