Shockley independently envisioned the FET concept in 1945, but he was unable to build a working device. The foundations of MOSFET technology were laid down by the work of William Shockley, John Bardeen and Walter Brattain. By the mid-1950s, researchers had largely given up on the FET concept, and instead focused on bipolar junction transistor (BJT) technology. The insulated-gate field-effect transistor (IGFET) was theorized as a potential alternative to junction transistors, but researchers were unable to build working IGFETs, largely due to the troublesome surface state barrier that prevented the external electric field from penetrating into the material. Junction transistors were relatively bulky devices that were difficult to manufacture on a mass-production basis, which limited them to a number of specialised applications. However, the JFET still had issues affecting junction transistors in general. Following Shockley's theoretical treatment on the JFET in 1952, a working practical JFET was built by George C. The static induction transistor (SIT), a type of JFET with a short channel, was invented by Japanese engineers Jun-ichi Nishizawa and Y. A JFET was first patented by Heinrich Welker in 1945. The first FET device to be successfully built was the junction field-effect transistor (JFET).

In the course of trying to understand the mysterious reasons behind their failure to build a working FET, it led to Bardeen and Brattain instead inventing the point-contact transistor in 1947, which was followed by Shockley's bipolar junction transistor in 1948. Shockley initially attempted to build a working FET, by trying to modulate the conductivity of a semiconductor, but was unsuccessful, mainly due to problems with the surface states, the dangling bond, and the germanium and copper compound materials.

The transistor effect was later observed and explained by John Bardeen and Walter Houser Brattain while working under William Shockley at Bell Labs in 1947, shortly after the 17-year patent expired. The concept of a field-effect transistor (FET) was first patented by the Austro-Hungarian born physicist Julius Edgar Lilienfeld in 1925 and by Oskar Heil in 1934, but they were unable to build a working practical semiconducting device based on the concept. Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1925.

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