AN OXYNITRIDE ISFET MODIFIED FOR WORKING IN A DIFFERENTIAL-MODE FOR PH DETECTION

Citation
V. Rocher et al., AN OXYNITRIDE ISFET MODIFIED FOR WORKING IN A DIFFERENTIAL-MODE FOR PH DETECTION, Journal of the Electrochemical Society, 141(2), 1994, pp. 535-539
Citations number
20
Categorie Soggetti
Electrochemistry
ISSN journal
00134651
Volume
141
Issue
2
Year of publication
1994
Pages
535 - 539
Database
ISI
SICI code
0013-4651(1994)141:2<535:AOIMFW>2.0.ZU;2-9
Abstract
In this study, we have shown that it is possible to deposit a silicon oxynitride membrane on silica ISFETs by plasma enhanced chemical vapor deposition (PECVD) and to develop a solid-state device for pH detecti on which works in a differential mode. Silicon technology using a new encapsulation technique and a new geometry of the ISFETs is described. The PECVD oxynitride membrane is deposited without damaging the struc ture. A nernstian stable pH response is obtained: 57.4 +/- 0.4 mV . pH -1 between pH 2 and 8.3 and it is only slightly affected by the concen tration of Na+ ions. Moreover, this silicon oxynitride membrane can be grafted with a long alkyl chain silane in order to make a REFET with a sensitivity of 36.3 +/- 0.3 mV . pH-1 between pH 3.3 and 8.1. The pH response of the solid-state device obtained (pH ISFET + REFET + plati num pseudo-reference electrode) is 23.4 +/- 0.2 mV . pH-1 from pH 2 to 8.