Semiconductor devices are electronic components with properties of semiconductor materials. Semiconductor materials include silicon, germanium, and gallium arsenide.
Thermionic devices or vacuum tubes have been replaced by semiconductor devices in several applications. Characteristically, electronic conduction in solid states prevails, as opposed to gaseous states or thermionic emissions in high vacuums. These are manufactured as single discrete devices, and as devices integrated into circuits known as integrated circuits or IC.
Semiconductor devices include two-terminal devices such as avalanche diodes or avalanche breakdown diodes, DIAC, diodes or rectifier diodes, gunn diodes, IMPATT diodes, laser diodes, light-emitting diodes or LED, photocells, PIN diodes, schottky diodes, solar cells, tunnel diodes, VCSEL, VECSEL, and zener diodes, three-terminal devices like bipolar transistors, darlington transistors, field effect transistors, IGBT or insulated gate bipolar transistors, SCR or silicon controlled rectifiers, thyristors, triacs, and unijunction transistors, four-terminal devices like hall effect sensors or magnetic field sensors and multi-terminal devices including charge-coupled devices or CCD, microprocessors, random access memory or RAM, read-only memory or ROM.