Prototype of micro ISFET for biomedical research

Shuichi Shoji*, Masayoshi Esashi, Tadayuki Matsuo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


With a view to developing an ion sensor capable of simple measurement of ion concentration at the cell level, a micro ionsensitive FET (micro ISFET) has been studied. For this purpose, it is necessary that the micro ISFET be a probe structure whose tip size is smaller than the cell and that the ion‐sensitive gate be placed at the tip of the probe. Special micro fabrication techniques are required for such a micro ISFET. This paper describes a three‐dimensional processing technique to fabricate a microprobe from an Si wafer and a method for forming an ISFET on a Si probe. Based on these fabrication techniques, a fundamental design of the micro ISFET is performed. An Si3N4 gate micro ISFET for pH is fabricated that has a tip size of 10 μm and a gate area of 5 × 5 μm2. Its characteristics are evaluated.

Original languageEnglish
Pages (from-to)21-29
Number of pages9
JournalElectronics and Communications in Japan, Part II: Electronics (English translation of Denshi Tsushin Gakkai Ronbunshi)
Issue number6
Publication statusPublished - 1986
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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