Miniature electronic circuits produced within and upon a single semiconductor crystal, usually silicon. Integrated circuits (ICs) range in complexity from simple logic circuits and amplifiers, about 1.3 mm (0.05 in.) square, to very large scale integrated circuits (VLSI), up to about 25 mm (1 in.) square. They can contain over 10⁹ transistors and other components that provide computer memory circuits and complex logic subsystems such as microcomputer central processor units (microprocessors) and digital signal processing (DSP).