Application of nickel electroless plating to the fabrication of low-cost backside contact ISFETs

Abstract

In this work an alternative, very simple, high-yield and low-cost technology for the fabrication of backside contacts ISFET sensors is presented. This new technological approach is based on the use of a nickel electroless plating technique for the selective metallization of the silicon electrical contacts. The need of any photolithographic step after the silicon anisotropic etch is avoided in this way and, therefore, the yield and the reliability of the whole fabrication process remains unaffected. The fabricated backside contacts ISFET devices has been tested successfully in a prototype of a whole chemical analysis system dedicated to the monitoring of the environment.