Very-large-scale Integration - History

History

During the 1925s, several inventors attempted devices that were intended to control the current in solid-state diodes and convert them into triodes. Success, however, had to wait until after World War II, during which the attempt to improve silicon and germanium crystals for use as radar detectors led to improvements both in fabrication and in the theoretical understanding of the quantum mechanical states of carriers in semiconductors, and after which the scientists who had been diverted to radar development returned to solid-state device development. With the invention of transistors at Bell labs, in 1947, the field of electronics got a new direction which shifted from power-consuming vacuum tubes to solid-state devices.

With the small and effective transistor at their hands, electrical engineers of the 50s saw the possibilities of constructing far more advanced circuits than before. However, as the complexity of the circuits grew, problems started arising.

One problem was the size of the circuits. A complex circuit, like a computer, was dependent on speed. If the components of the computer were too large or the wires interconnecting them too long, the electric signals couldn't travel fast enough through the circuit, thus making the computer too slow to be effective.

Jack Kilby at Texas Instruments found a solution to this problem in 1958. Kilby's idea was to make all the components and the chip out of the same block (monolith) of semiconductor material. When the rest of the workers returned from vacation, Kilby presented his new idea to his superiors. He was allowed to build a test version of his circuit. In September 1958, he had his first integrated circuit ready. Although the first integrated circuit was pretty crude and had some problems, the idea was groundbreaking. By making all the parts out of the same block of material and adding the metal needed to connect them as a layer on top of it, there was no more need for individual discrete components. No more wires and components had to be assembled manually. The circuits could be made smaller, and the manufacturing process could be automated. From here, the idea of integrating all components on a single silicon wafer came into existence and which led to development in small-scale integration (SSI) in the early 1960s, medium-scale integration (MSI) in the late 1960s, and then large-scale integration (LSI) as well as VLSI in the 1970s and 1980s, with tens of thousands of transistors on a single chip (later hundreds of thousands, then millions, and now billions).