A hydrophobic polymer such as parylene has ion dissociation sites of extremely low density. An electrolyte-Parylene interface manifests a constant potential independent of solution composition. Thus the parylene-gate ISFET can be used as a solid-state reference electrode. These films can be used for the substrate of a CHEMFET using recent chemical modification technology. The concept of a parylene-gate ISFET based on the site binding model is addressed. A probe-type all-solid-state pH sensor integrating a Si//3 N//4 gate, a parylene gate and an Au pseudoreference electrode is discussed, and a pH ISFET modified chemically with crown ether compounds is presented.
|Number of pages||4|
|Publication status||Published - 1985|
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