Hello Kagan The TiO2 layer is made by Atomic Layer Deposition on a PE-CVD-Silicondioxide using an aluminum oxide buffer. So there shouldn´t be a lot of defects Regards Florian Michael Larsson schrieb: > Hi Kagan, > > My suggestion was to use SC1, rather than Piranha to wet-clean the TiO2 > layer. I have no practical experience to back-up my comments unfortunately, > but I am unaware of any wet etchants capable of high etch rates in Ti that > don't either include HF or -Cl groups. With regard to TiO2, this is > the product formed when Ti oxidises under galvanic attack. Once grown, the > oxide acts as a barrier, inhibiting further chemical attack. The ability to > protect underlying Ti from oxidation can obviously be reduced when > considering a deposited layer (with defects) relative to pure, bulk > material. Nevertheless, theory would suggest that an SC1 clean > (NH4OH:H2O2:H20) should not attack Ti, and certainly not it's chemically > inert oxide; even if this is indeed formed during the SC1 clean. > > Florian: is the layer sputtered or evaporated?