The Integrated Circuit
The Integrated Circuit
Throughout history, military needs (and military budgets) have spurred technological innovation. During the Cold War, demand for increasingly complex yet smaller, lighter, and more reliable electronic equipment fed the quest for better ways to package transistors.
Modules and “hybrid” microcircuits squeezed components into miniature enclosures. But engineers dreamed of fabricating multiple devices and interconnections on a single piece of semiconductor material.
With the advent of the transistor and the work in semiconductors generally it seems now possible to envisage electronic equipment in a solid block with no connecting wires.
A Solid Block Without Wires
Beginning in the mid-1950s, several research groups and scientists, including G.W.A. Dummer himself in the U.K., embarked on projects aimed at realizing Dummer’s vision of a complete electronic circuit on a single piece of semiconductor material.
Different teams followed different paths.
Engineers at Bell Labs and IBM independently built complex multi-junction devices that operated as digital counters. The Air Force funded RCA to make integrated logic gates and shift registers. William Shockley became obsessed with developing a four-layer diode switch, which led to his company’s downfall. Westinghouse even pursued an idea proposed by MIT professor Arthur von Hipple that involved arranging materials at the molecular level to perform electronic functions.
Until 1958, however, nobody had demonstrated a general-purpose solution.
I.M. Ross, H.H. Loar and L.A. D'Asaro of Bell Labs described the stepping transistor, used to create a single-chip, four-stage counter for telephone system applications, in 1956.View Artifact Detail
Ross (later president of Bell Labs) at left and D’Asaro at work in the lab.View Artifact Detail
Kilby’s Flying Wires
Texas Instruments hired Jack Kilby to design transistor circuit modules. Kilby had other ideas.
Believing the modules a dead end, he spent TI’s company-wide summer vacation in 1958 looking for an alternative. Kilby etched separate transistor, capacitor, and resistor elements on a single germanium slice, then connected them with fine gold “flying” wires into oscillator and amplifier “solid circuits.”
TI introduced Kilby’s Type 502 Binary Flip-Flop in 1959. Although Kilby’s hand-crafted solid-circuit approach was impractical for mass production, his work pointed the way to a practical monolithic solution.
The separate components on this TI Type 502 bistable multivibrator circuit were electrically isolated from each other by air gaps etched in the silicon, and interconnected by fine gold “flying wires.”View Artifact Detail
Fine gold “flying wires” interconnected the separate functional components on this Texas Instruments “solid circuit” chip.View Artifact Detail