Iridium was sputtered as the top layer of stimulation electrodes. The coatings were varied in their morphology by adjusting the total deposition pressure and the working distance (WD) of target and substrate. It is shown that the resulting different kinds of morphologies have a strong influence on stimulation characteristics. The combination of high working gas pressure and small WD as well as the combination of medium working gas pressure and larger WD yield the best characteristics on macro-sized test electrodes.
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