Method for fabricating an implantable electrode

Abstract

A method for fabricating an implantable medical electrode includes roughening the electrode substrate, applying an adhesion layer, and depositing a valve metal oxide coating over the adhesion layer under conditions optimized to minimize electrode impedance and post-pulse polarization. The electrode substrate may be a variety of electrode metals or alloys including titanium, platinum, platinum-iridium, or niobium. The adhesion layer may be formed of titanium or zirconium. The valve metal oxide coating is a ruthenium oxide coating sputtered onto the adhesion layer under controlled target power, sputtering pressure, and sputter gas ratio setting optimized to minimize electrode impedance and post-pulse polarization.

1 - 2 . (canceled) 
     
     
         3 . The method of  claim 21  wherein the mechanical roughening of the electrode surface comprises grit blasting. 
     
     
         4 . The method of  claim 3  wherein the grit blasting is performed using an alumina oxide media. 
     
     
         5 . The method of  claim 21  wherein the cleaning of the roughened electrode surface is carried out. 
     
     
         6 . The method of  claim 5  wherein the cleaning comprises ultrasonic cleaning. 
     
     
         7 . The method of  claim 21  wherein the sputtering process parameters are optimized to minimize post-pulse polarization 
     
     
         8 . The method of  claim 7  wherein the sputtering process parameters, optimized to minimize post-pulse polarization, include a target power. 
     
     
         9 . The method of  claim 8  wherein the target power is about 300 Watts. 
     
     
         10 . The method of  claim 7  wherein the sputtering parameters optimized to minimize post-pulse polarization include a sputtering pressure. 
     
     
         11 - 12 . (canceled) 
     
     
         13 . The method of  claim 21  wherein the adhesion layer comprises a metal selected from the group of titanium and zirconium. 
     
     
         14 . The method of  claim 5  the cleaning comprises ion-etching the roughened electrode surface prior to depositing the adhesion layer. 
     
     
         15 - 20 . (canceled) 
     
     
         21 . A method for fabricating an implantable medical electrode, the method consisting essentially of:
 mechanically roughening a surface of the substrate;   optionally cleaning the roughened substrate surface;   applying an adhesion layer to the roughened substrate surface; and   applying a metal oxide coating directly on the adhesion layer on the roughened surface using sputtering in a sputtering atmosphere comprising a 25% ratio of oxygen to argon.   
     
     
         22 . The method of  claim 21 , wherein the metal oxide coating comprises iridium. 
     
     
         23 . The method of  claim 21 , wherein the metal oxide coating comprises ruthenium.