Wet etching of TiO2

Hi, all,
Anyone here know how to wet etch TiO2? I just want to etch thin film of TiO2 to expose the bottom electrode. I have checked some papers and
there are several reported method such as using H2SO4, HF & HNO3, HF & NH4F. However, the details about the required purity or mixing ratio was not there. Anyone can provide me of more details? Thanks very much!
Btw, the TiO2 thin film was got from sol-gel method and was deposited on Si wafer. Since TiO2 is very difficult to etch, is it possible to let the bottom electrode exposed during other processes? Anyone has suggestions or similar experiences?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.