The Integrated Circuit — Putting the Whole Transistor Radio on One Chip

Jack Kilby's 1964 monolithic integrated circuit patent at Texas Instruments — the invention that put multiple electronic components on a single piece of semiconductor, enabling the miniaturization of all modern electronics.

What it covers

This patent describes a 'monolithic' integrated circuit — a device where multiple electronic components (transistors, resistors, capacitors) are all fabricated within a single continuous piece of semiconductor material, rather than as separate components wired together. The word 'monolithic' means 'one stone' — every component is made from the same slab of germanium or silicon. Tiny regions of the semiconductor are doped with different impurities to create transistors in some areas, resistors in others, and capacitors between conducting layers. Interconnecting wires are formed on the surface of the chip by depositing thin metal traces. The result is a complete electronic circuit in a package that can be manufactured automatically and made extremely small.

What it doesn't cover

• —The planar process — Noyce's complementary patent (US2981877) covers the specific manufacturing technique that made ICs practical
• —CMOS logic — the dominant IC technology today uses a different transistor type than Kilby's original
• —Programmable chips (FPGAs, CPUs) — this patent covers the fabrication concept, not specific circuit architectures
• —Packaging and interconnects between chips — this covers what's on a single semiconductor die, not how chips connect to each other

The clever bit

Kilby made his key insight in the summer of 1958, just two months after joining Texas Instruments — he was too new to the company to take the summer vacation that most employees took, so he worked alone in an empty lab. The established approach to electronic circuits was to build them from discrete components — each transistor, resistor, and capacitor was a separate manufactured part that had to be soldered together. The fundamental insight was that all of these components could be made from the same semiconductor material. Once you accept that, the entire circuit can be fabricated in one process, on one substrate. Kilby demonstrated his first working integrated circuit — a phase shift oscillator — on September 12, 1958. It was a tangled mess of wires and germanium, but it worked.

Why it matters

Kilby won the Nobel Prize in Physics in 2000, alongside Herbert Kroemer and Zhores Alferov. His co-inventor Robert Noyce (Fairchild, US2981877) had died in 1990 and was not eligible. The Nobel Committee's citation credited Kilby with 'his part in the invention of the integrated circuit.' The IC is the fundamental reason that computers went from buildings to desks to pockets. Moore's Law — the observation that the number of transistors on a chip doubles every two years — is a direct consequence of the integrated circuit enabling systematic miniaturization of the same basic structure Kilby patented.

Real-world examples

• 1.Texas Instruments' first commercial product based on this patent was a hearing aid chip (1962), followed by the U.S. Air Force purchasing ICs for Minuteman missile guidance computers
• 2.The Apollo spacecraft's guidance computer used integrated circuits from Fairchild Semiconductor — buying enough of them to drive the price down from $1,000 per chip to $25
• 3.The Intel 4004 (1971) — the first microprocessor — contained 2,300 transistors on a single IC. The iPhone 15's A17 chip contains 19 billion.

Glossary