An Astonishing Accident

In 1916, Jan Czochralski, a Polish chemist working in the Berlin laboratory of the AEG electrical company, made an accidental discovery that changed the course of history. Exhausted from research aimed at finding a method to measure the crystallization rate of metals, Czochralski made a seemingly trivial mistake. Intending to record his observations, he instinctively dipped his pen not into an inkwell but into a nearby crucible of molten tin. To his surprise, when he withdrew the pen, a thin thread of solidified metal hung from the nib. This unexpected appearance of a metal thread intrigued him. He repeated the action, dipping the nib into the molten tin and slowly withdrawing it. He observed the formation of another thread. When he pulled the pen out faster, the thread was shorter. A series of systematic experiments conducted that evening confirmed that the speed at which the pen was withdrawn from the molten metal affected the length and structure of the solidified thread. He realized that this phenomenon could provide key insights into the crystallization properties of metals.

Czochralski noted that the notch in the pen’s nib acted like an open capillary; crystallization in capillary tubes had previously been described by Gustav Tammann. The Polish scientist thus replaced the pen with a glass tube and the hand with a clockwork mechanism. This allowed him to control the speed of pulling the crystalline thread.

This accidental experiment, later named the Czochralski method and first published in 1918, marked a breakthrough in the technology for producing single crystals essential for semiconductor electronics.

In 1950, across the Atlantic, American scientist Gordon Teal struggled with the challenge of obtaining large, high-quality germanium single crystals for transistors. It turned out that the Czochralski method, used in metallurgical laboratories, was suitable for this purpose after necessary improvements. Later, Teal applied the method to produce silicon crystals. Without the Czochralski method, the development of microprocessors, computers, mobile phones, and many other devices would have been impossible. The simplicity and versatility of the method made it the foundation of the technological revolution, securing its place in laboratories and electronics companies worldwide.

Jan Czochralski, born in 1885 in Kcynia, in a Poland divided by partitions, was a self-taught chemist who rose to the heights of science. Despite lacking formal higher education, he worked in Berlin’s chemical and metallurgical industries, leading the metals laboratory at AEG. His accidental discovery in 1916 was not merely a stroke of luck but a testament to his abilities and scientific rigor. After returning to Poland in 1928, he became a professor at the Warsaw University of Technology. Unfortunately, in 1945, he was not allowed to return to the university for reasons that remain unclear. He spent his final years in Kcynia, running a small chemical plant called BION. He died in 1953. It was not until 2011 that the Warsaw University of Technology officially recognized his contributions, lifting the infamy imposed decades earlier.

Czochralski named his crystallization rate measurement method the “capillary method” (Capillarverfahren, Capillarmethode), referring to the initial suction of molten material through a capillary at the end of a hook. The first description of the method, titled “Ein neues Verfahren zur Messung der Kristallisationgeschwindigkeit der Metalle” (“A New Method for Measuring the Crystallization Rate of Metals”), was published in the journal Zeitschrift für physikalische Chemie in 1918. The manuscript was received by the editors on August 19, 1916—a date considered the birth of the method. The publication detailed the technical aspects and results of initial experiments on tin, zinc, and lead.

The natural consequence of this discovery was the application of the “crystallization rate measurement method” to the production of single crystals. As early as August 1918, Hans Joachim von Wartenberg used this method to obtain zinc crystals, being the first to replace the capillary with a crystal seed. Further modifications were proposed by, among others, Ervin von Gomperz (1922), H. Mark and collaborators (1923), and E.G. Linder (1925).