PMID-18640155 Characterization of flexible ECoG electrode arrays for chronic recording in awake rats.
- Yeager JD1, Phillips DJ, Rector DM, Bahr DF.
- We tested several different adhesion techniques including the following: gold alone without an adhesion layer, titanium-tungsten, tantalum and chromium.
- All films were DC magnetron sputtered, without breaking vacuum between the adhesion layer (5nm) and gold counductor layer (300nm).
- We found titanium-tungsten to be a suitable adhesion layer considering the biocompatibility requirements as well as stability and delamination resistance.
- While chromium and tantalum produced stronger gold adhesion, concerns over biocompatibility of these materials require further testing.
- Thought: use tantalum directly, no Ti needed.
- Much better than Cr -- much more ductile and biocompatible.
- Caveat: studies showing reduction to stociometric Ta results in delamination.
- Ta conductivity: 1.35e-7 Ohms * m; Ti 4.2e-7; 3x better (film can be 3x thinner..)
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