INVERTED ISFET

摘要

An inverted ion-sensitive field effect transistor (ISFET) (10) comprises a substrate layer (11), a sensing membrane (12) on said substrate layer (11), a layer of field oxide (19 ) on said sensing membrane (12), doped source (13) and drain (14) regions on said layer of field oxide (19), and characterized in that electrical contacts (16, 17) are provided to the respective source (13) and drain (14) regions on the opposing side of said sensing membrane (12) and said substrate layer (11) is windowed with an opening access (18) to said sensing membrane (12) to provide electrical isolation of the electrical contacts (16, 17) from said sensing membrane (12).