Lely method

The patent for this method was filed in the Netherlands in 1954 and in the United States in 1955 by Jan Anthony Lely of Philips Electronics.

[1] The patent was subsequently granted on 30 September 1958, then was refined by D. R. Hamilton et al. in 1960, and by V. P. Novikov and V. I. Ionov in 1968.

[2] The Lely method produces bulk silicon carbide crystals through the process of sublimation.

Silicon carbide powder is loaded into a graphite crucible, which is purged with argon gas and heated to approximately 2,500 °C (4,530 °F).

[2] Several modified versions of the Lely process exist, most commonly the silicon carbide is heated from the bottom end rather than the walls of the crucible, and deposited on the lid.

A diagram of the modified Lely method, showing a graphite crucible surrounded by induction coils for heating. Silicon carbide charge is sublimated from the bottom of the chamber and deposited on the upper lid, which is cooler.