Piranha or base piranha solution would do the trick depending on whether or not you have non-detachable components. If not or if the components are stable in bases or acids it works well. The same considerations apply if you have a plasma oven handy. Hydrogen plasma works nicely but oxygen plasma should do just as well. Sadly, I don't know how your electrode is constructed so I can't say for sure if these solutions work for you. Good luck and be careful with the piranha solutions should you choose to go that way ;)

Thank you so much Mark. My electrodes are fabricated on Glass wafer, made by gold film about 100 micrometer. Passivation layer is by SiO2. However, on top of electrodes, there are 3D structure made of SU8.

Hmm, Su8 and Piranha does not mix well - to my knowledge -, meaning that Piranha or Aqua regia are good methods to clean SU8 off substrates. Mild Plasma treatment with O2 Plasma should do the trick. You have to take care however that the plasma oven is not used for other sensitive surface patterning procedures. I never used SU8 but there was a problem with weird contaminations in the Plasma oven when hydrogels where treated in there. Might have been Lab-Vodoo but check with the owners of the Plasma oven before you use it. Alternatively there are also Plasma-Pens that are easier to use but a bit more exotic. The problem will be to make sure that you actually got the contaminating molecules off completely. If complete removal is important to you then you will have to verify the first few times with NEXAFS or XPS (both should work if I remember correctly - depends on what is closest at hand)

Should you not have the skills and licences to operate the spectroscopes by yourself remember to bring a pound of coffee or chocolate for the people who do the actual work ;) It greases the engines nicely and is proper etiquette.

oxygen plasma or uv-ozone should do the trick

Aqua Regia is not a good solution. It can etch gold.

Thank you so much Andrew Stuart and Veeradasan Perumal

Hello, Tien Anh Nguyen

I am also at the same point, I want to clean SAM from gold chip, Could you please share your experience. What did you find best to clean?

Thanks

Hello Andrew Stuart

what is the condition to apply in the oxygen plasma that you recommend?

best wishes

Miguel Monteiro