MANUFACTURE OF ION-SENSITIVE FIELD EFFECT TRANSISTOR HAVING TA2O5 HYDROGEN ION-SENSITIVE FILM

摘要

PURPOSE: To obtain a method by which an ion-sensitive field effect transistor(ISFET) which has high sensitivity, a stable operating characteristic, and a Ta₂O₅ hydrogen ion-sensitive film and to which a wafer unit process can be adopted and the productivity and stability of an element are largely improved. ;CONSTITUTION: In a method for forming Ta₂O₅ film, a Ta₂O₅ film is heat-treated for about one hour at 375-450°C in an oxygen atmosphere after the film is formed on the Si₃N₄/SiO₂ gate insulating film of a pH-ISFET manufactured to a thickness of 400-500Å by the well known method by using an RF reactive sputtering method. The Ta₂O₅ formed on the other part than the gate area of the pH-ISFET can be removed by using a lift-off method utilizing a positive photosensitive film.;COPYRIGHT: (C)1993,JPO