FETセンサ

抄録

An FET sensor is an integrated device of the insulated gate field effect transistor (IGFET) and the chemical sensor and therefore is named as chemically sensitive field effect transistor (CHEMFET). In the CHEMIFET, the gate metal is replaced a more complex structure having chemically sensitive layer. CHEMFETs are new type of chemical sensors and have potential advantages over conventional chemical sensors in miniatuarization, robust solid state nature, mass productivity etc. According to the nature of the interaction between the species to be detected and the chemically sensitive layer, CHEMFETs can be divided into two groups : one that will measure gas concentrations, for example Pd gate FET (H₂ gas sensor) and the other that will measure ion concentrations in the solution. The latter called an ion sensitive FET (ISFET). This paper describes the present status of ISFET, that is, its histoical survey, principle, fabrication method and ion selectivities.