Complementary metal-oxide-semiconductor Circuits

Miniaturization of electronic devices in integrated circuits (ICs) has both technological and physical limits. Since 30-40 years only a semiconductor technology, mostly the CMOS FET (complementary metal-oxide-semiconductor field effect transistor) and the TTL (transistor-transistor logic) technologies are used for fabrication of integrated circuits in the industrial scale. Probably the CMOS technology will be used at least in the next 10-15 years. 

Organic semiconductors are used in many active devices. Many can be processed in solution and can therefore be printed. The charge transport properties largely depend on the deposition conditions, which are influenced by the nse of solvents, the deposition technique, concentration, interfaces and so on. Most of the organic semiconductors used today are p-type (e.g., pentacene and polythiophene), but the first n-type materials have also become available and these mean that complementary metal-oxide-semiconductor (CMOS) circuits can now be fabricated. 

The source and drain are both p-type if the current flowing is holes. Surface field effect transistors have become the dominant type of transistor used in integrated circuits, which can contain up to one billion transistors plus resistors, capacitors, and the very thinnest of deposited connection wires made from aluminum, copper, or gold. The field effect transistors are simpler to produce than junction transistors and have many fevorable electrical characteristics. The names of various field effect transistors go by the abbreviations MOS (metal-oxide semiconductor), PMOS (p-type metal-oxide semiconductor), NMOS (n-type metal-oxide semiconductor), CMOS (complementary metal-oxide semiconductor—uses both p-type unipolar and n-type unipolar). 

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