Prototype sodium and potassium sensitive micro ISFETS

Yoshinori Ohta, Shuichi Shoji, Masayoshi Esahi, Tadayuki Matsuo

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Design and fabrication methods, along with the results of a preliminary evaluation, are described for microprobe ISFET sensors intended for extracellular ion-activity measurements. The devices are 5 mm long with a gradual taper to the tip where the cross-sectional area is 30 × 30 μm2. Since the ion-sensing area is located at the end of the tip, a very small sensing region is achieved. Photo-induced noise generated in the depletion zone of the long drain diffusion layer was found to be particularly troublesome. This effect was greatly reduced by the use of an opaque tantalum thin film deposited on the probe surface. Preliminary tests of micro pH, pNa and pK ISFETs have shown that it is possible to measure extracellular ion activities using ISFETs.

Original languageEnglish
Pages (from-to)387-397
Number of pages11
JournalSensors and Actuators
Volume2
Issue numberC
DOIs
Publication statusPublished - 1981 Jan 1

ASJC Scopus subject areas

  • Engineering(all)

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