Metal semiconductor FET

Metal selenides, 22 87 Metal semiconductor FETs (MESFETs), 22 163. See also Field effect transistors (FETs)... 

Figure 14-6. Schematic view of three kinds of field-effect transistors (FET) (a) metal-insulator-semiconductor FET (MISFET), (b) metal-semiconductor FET (MESFET), (c) thin-film transistor (TFT).

Field-effect transistors (FETs) Heterojunction bipolar transistors (HBTs) High electron mobility transistors (HEMTs) Metal oxide semiconductor FETs (MOSFETs) Single-electron transistors (SETs) Single-heterojunction HBTs (SH-HBTs) Thin-film transistors (TFTs) hydrogenated amorphous silicon in, 22 135... 

Variation of the nature of the gate electrode results in the different types of FET. For example, in the metal oxide semiconductor FET (MOS-FET) palladium/palladium oxide is used as the gate electrode. This catalyti-cally decomposes gases such as hydrogen sulphide or ammonia with the production of hydrogen ions, which pass into the semiconductor layer. An enzyme may be coated on the palladium, e.g. urease, which catalyses the production of ammonia from urea and thus provides a device for the measurement of this substrate. 

Fig. 1. (a) Structure of eui ion-sensitive FET transducer with single FET element, (b) Structure of an ion-sensitive FET with metal oxide semiconductor FET. D, drain S, source IG, ion-sensitive gate CP, contact pad G, gate RE, reference electrode AS, analyte solution MOSFET, metal oxide semiconductor FET ISFET, ion-sensitive FET. 

---