IODIDE ION-SENSITIVE FIELD-EFFECT STRUCTURES

A new ion-selective thin-film membrane for ion-sensitive field-effect structures has been realized. Silver iodide (AgI) as an iodide-sensiti ve material has been vacuum evaporated onto semiconductor-insulator su bstrates. Various preconditioning and vacuum evaporation parameters as well as post treatment conditions were tested. Sensitivity and select ivity of these model field-effect structures were investigated by capa citance-voltage (CV) measurements. Nernstian behaviour, good selectivi ty and a high lifetime comparable with that of the ion-selective elect rode (ISE) could be obtained. This method of membrane fabrication is e xpected to be suitable for the large scale manufacture of sensor chips .