After the invention and mass production of transistors, various solid-state semiconductor components such as diodes and transistors were widely used, replacing the functions and roles of vacuum tubes in circuits. By the middle and late 20th century, the progress of semiconductor manufacturing technology made integrated circuits possible. Compared with manually assembled circuits using individual discrete electronic components, integrated circuits can integrate a large number of microcrystalline tubes into a small chip, which is a great progress. The scale production capacity, reliability and modular method of circuit design of integrated circuits ensure the rapid adoption of standardized integrated circuits instead of discrete transistors.
Integrated circuits have two main advantages over discrete transistors: cost and performance. The low cost is due to the fact that the chip prints all components as a unit through photolithography, rather than making only one transistor at a time. The high performance is due to the fast switching of components, which consumes less energy, because the components are small and close to each other. In 2006, the chip area ranged from a few square millimeters to 350 mm ²， Per mm ² It can reach onemillion transistors.
The first prototype of integrated circuit was completed by Jack Kilby in 1958, including a bipolar transistor, three resistors and a capacitor.
According to the number of microelectronic devices integrated on a chip, integrated circuits can be divided into the following categories:
Small scale integration (SSI) has less than 10 logic gates or less than 100 transistors.
There are 11-100 logic gates or 101-1k transistors in medium scale integration (MSI).
There are 101~1k logic gates or 1001~10k transistors in large scale integration (LSI).
There are 1001-10k logic gates or 10001-100k transistors in very large scale integration (VLSI).
There are 10001-1m logic gates or 100001-10m transistors in ULSI.
Glsi (full English Name: Giga scale integration) has more than 1000001 logic gates or more than 10000001 transistors.
