Dear Mikas, I have two ideas regarding your problem: 1) You may try deposition of Ti just before depositing gold without breaking the vacuum. I think it will adhere well both to Ti (TiO2) and Au. 2) I do not whether it works but you can try a quick dip of Buffered HF to remove the thick oxide on top of Ti, then place the wafer to the chamber of the evaporator. Regards, Kagan TOPALLI, Ph. D. Senior Research Engineer METU-MEMS Center Middle East Technical University TR-06531 Ankara Turkey Phone: +90 312 210 45 46 Fax: +90 312 210 23 04 http://www.mems.eee.metu.edu.tr/~topalli/ -- mikas remeika wrote: > Hello, > > does anybody have experience dealing with this kind of issue: > > I'm trying to deposit a film of gold on top of a thin film of titanium > (e-beam evaporated), the titanium is exposed to air (and oxygen plasma) > during previous processing, so its inevitable that there is a thin layer of > oxide on the surface of the titanium. > > A Gold film is e-beam evaporated onto the surface of the Ti (TiO2). > Resulting film adheres well enough to perform lift-off, however, mechanical > stress such as wireboding results in large sections of the gold film peeling > off. I have tried evaporating a fresh layer of Ti under the gold (in the > same vacuum), that did not give any improvement in adhesion. I also have > access to sputtering machines, however in previous experience evaporated > gold adhered more reliably to different surfaces. > > So my question - is there are way to treat the titanium/TiO2 surface to > create good adhesion to the gold layer? I have acceess to a range of > materials for sputtering and evaporation, if there is a specific material > that adheres well to both gold and TiO2 I would really like to know what it > is. > > Some notes: The sample in this case cannot be heated to more than 100C and > cannot be exposed to RIE type plasma. Also, it is necessary to have > electrical contact between the gold and titanium (the naturally formed oxide > in this case does not create electrical insulation).