Integrated circuits ICs, also called microelectronic circuits or chips. It is a set of electronics components and fabricated as a single unit, in which micro active devices such as diodes and transistors and passive devices such as capacitors and resistors and their interconnections are built up on a thin substrate of semiconductors materials such as silicon. When the transistor discovery by William Shockley and his team at the American Telephone and Telegraph Company’s Bell Laboratories occurred in 1947,  the integrated circuits were created.

 Shockley’s team ( John Bardeen and Walter H. Brattain) found that the electrons can create a barrier on the surface of certain crystals under the right conditions and learned to control electricity flow through the crystal by controlling this barrier. Controlling electrons flow through a crystal enabled the team to create a device capable of performing certain electrical operations, such as signal amplification performed by vacuum tubes beforehand.
They called this device a  transistor which form from a combination of conductors and resistors. This type of electronics with solid materials has become known as solid-state electronics. Solid-state devices proved to be more rigid, easier to work, reliable, smaller, and less expensive than vacuum tubes. So, we deduce that any IC consisting of a large number of transistors. The next videos explain by animation how the transistors work.