The Invention of the Modern Field-Effect Transistor

This 1960 patent describes the fundamental structure of the MOSFET, the tiny electronic switch that powers every modern computer processor.

What it covers

The patent describes a semiconductor device that uses an electric field to control the flow of current between two regions of the same conductivity type, separated by a region of the opposite type. By placing a dielectric (insulating) layer over the surface and applying a voltage, the device creates an electric field that modulates the conductivity of the channel between the two P-N junctions. This mechanism allows a small input voltage to act as a gate, effectively turning the flow of electrons on or off, which is the basic requirement for binary logic in digital circuits.

What it doesn't cover

• —Does not cover bipolar junction transistors (BJTs) which rely on current injection rather than electric field control.
• —Does not cover vacuum tubes or other non-semiconductor switching technologies.
• —Does not cover specific manufacturing lithography techniques used to build these devices at scale.

The clever bit

The innovation was using an insulating dielectric layer to isolate the control gate from the semiconductor, preventing current leakage into the gate while still allowing the electric field to influence the channel.

Why it matters

This is the foundational patent for the Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). It is arguably the most important patent in the history of computing, as it enabled the miniaturization of transistors that allowed for the creation of integrated circuits and microprocessors.

Real-world examples

• 1.Modern computer CPUs (Intel Core, AMD Ryzen)
• 2.Smartphone processors (Apple A-series, Qualcomm Snapdragon)
• 3.Computer memory chips (DRAM and Flash storage)