ANION-SELECTIVE FIELD-EFFECT TRANSISTOR SENSOR USING ION-BEAM SPUTTERING FILM OF ALKALI METAL-FREE LEAD PHOSPHATE GLASS CONTAINING SILVER OXIDE

Abstract

The specific responsive ISFET were made by a modification on its gate surface with some ion selective materials. In order to make adequate device of an ISFET which indicates an anionic responsive characteristics, the gate surface was coated by an ion-beam (IB) sputtering method using a improved alkali metal-free lead phosphate glass containing silver oxide. When a radio frequency (RF) sputtering method was used, the gate channel would be exposed to bombardment by electron, uv light and soft X-ray, and makes the static characteristics of ISFET worse. On the contrary, when the IB sputtering method was used, the static characteristics did not change and the sputtering damage could be neglected. With this processing technique, damageless anion specific ISFET can be fabricated without annealing. Fabrication conditions of the glass coated ISFET and the anion responsive behavior were discussed.