Fabrication of ion-sensitive field effect transistors using a silicon-on-sapphire

Abstract

Ion-sensitive field effect transistors (ISFET) were fabricated using a silicon-on-sapphire wafer. Since this ISFET was made on the insulator, the leakage current was greatly decreased. Also the manufacturing process was simplified and the mechanical strength of the device was increased by using the sapphire. The sensitivity to hydrogen ion of this sensor was the same as that of the ISFET made of usual Si wafer, and the electrode responded in the pH 210 range with a slope of about 52 mV decade-1.