Platinum-Platinum Oxide Gate pH ISFET

Abstract

Platinum-platinum oxide gate ISFETs (ion sensitive field effect transistors) have been designed and fabricated for a stable pH microsensor. The platinum oxide layer, formed by a new fabrication process using an RF sputtering technique, was identified as PtO2 by X-ray photoelectron spectroscopy. The pH response of the platinum-platinum oxide gate ISFET was linear in the pH range between 1 and 10, and a sensitivity of 40.5±4.0 mV/pH was obtained. The ISFET developed had better stability than a conventional Si3N4 bare gate ISFET.