Although the term is sometimes used to describe discrete electronic components assembled in an extremely small and compact form, it is often taken as a synonym for integrated circuit technology. Microelectronic tuned circuits can be built using piezoelectric electromechanical components.
Hybrid microcircuits contain a mixture of discrete and integrated circuits on a single substrate.
The major fabricating steps include film formation, impurity doping, photolithography, and packaging. Silicon oxide, also called silica, is grown on the surface of the silicon during the film-formation stage. After exposure, the silicon wafer is developed, and the unwanted areas of the oxide are removed by an etching process. Additional layers of silicon are deposited to create bipolar transistors . Metal, usually aluminum, is deposited where contacts are desired.