Prototype sodium and potassium sensitive micro ISFETS

Yoshinori Ohta*, Shuichi Shoji, Masayoshi Esahi, Tadayuki Matsuo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


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
Issue numberC
Publication statusPublished - 1981
Externally publishedYes

ASJC Scopus subject areas

  • General Engineering


Dive into the research topics of 'Prototype sodium and potassium sensitive micro ISFETS'. Together they form a unique fingerprint.

Cite this