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Etching titanium

 

Dear colleagues,

I want to etch 5 nm of titanium nanostructures using 20 nm of gold as mask. My question is : is there a chemical solution or a special gas plasma that I can use without damaging the gold surface?

Amira Lebib
University of Physics - Wuerzburg, Germany

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Etching titanium with a gold mask should be quite fast with hydrofluoric acid. However undercut would be severe if since 90+% of the time is spent removing the native oxide on titanium. Once the native oxide is gone, the etch rate becomes very high. I would use dilute HF if you try this approach, possibly <1%. If you are etching nanostructures, don't even try HF.

Dry etching Ti is rather easy with a fluorine containing gas such as SF6 or CF4 or NF3. If anisotropy is desired, you must lower the pressure and operate in reactive ion etch mode (RF power to the sample electrode and ground the counter electrode).

Ian Yee
- Austin, Texas