生化離子感測器

This invention provides two types of biochemical ion sensors, one of which using an ion sensitive field effect transistor (ISFET), formed by combining enzymes and the ISFET as the basis, in which the entire gate is replaced with the oxide layer of rare earth elements, or other low-impedance materials of III-V, II-VI and IV-IV groups, such as IRO2, ZnO2, TiO2 and WO3 to provide the biochemical ion sensor with lower electric current leakage and to improve the sensing result and speed. Due to the characteristics of the oxidation layers of rare earth elements, this invention ensures the biochemical ion sensor to have lower electric current leakage while the biochemical ion sensor can have better sensing effect as compared with conventional art. Another type of biochemical ion sensor is an extended gate ion sensitive field effect transistor (EGFET), where the gate portion of a MOSFET is extended to independently form a sensing zone and separate from the MOS capacitor element per se to allow repeated use of the MOS capacitor element. This structure is suitable for the use of the disposable bio-medical sensors to further facilitate commercialization of EGFET.