English: A silicon crystal being grown by the Czochralski process at the Raytheon Corp. semiconductor plant in Newton, Massachusetts, USA, in 1956 for use in the first silicon transistors. The transistor was invented in 1946, and the Czochralski process was first used to grow silicon crystals to make the first silicon transistors at Bell Labs in 1953, so this is one of the earliest silicon crystal production plants.

The induction heating coil visible around the crucible carries a radio frequency current, and the heat induced melts the pure silicon in the crucible at a temperature of 2650°F. A seed crystal of solid silicon is attached to the rod and is lowered into the tube to touch the surface of the melted silicon. By carefully controlling the temperature distribution using the induction heater, the melted silicon is induced to crystallize on the seed, adding to the crystal. The seed is slowly pulled up from the melt, and the silicon freezes onto the end, creating a solid rod of monocrystal silicon. Here the process has just begun, and the tapered end of the crystal is visible just below the rod. In this early device the silicon crystal was only 1 inch wide. The woman is measuring the temperature of the melt with an optical pyrometer. This device has a filament attached to a calibrated current source inside the viewing tube, which appears silhouetted in front of the hot silicon. The technician turns up the current until the luminous filament just disappears against the background of the glowing silicon. This means the filament and the silicon are at the same temperature. The current knob (bottom) is calibrated in temperature, so she can read the temperature of the silicon off the knob.

Alterations to image: Cropped out portions of magazine cover containing text, straightened, removed obvious dirt and damage.