Directly heatable silicon or silicon carbide tubular furnace - has thicker insulation at ends extending constant temp. zone, useful for semiconductor prodn.

摘要

Prodn. of directly-heatable Si or SiC tubular furnaces for diffusion (and tempering) processes in semiconductor technology involves deposition of Si or SiC from the gas phase on the surface of a heated support, which is then removed. A (partly)doped layer is formed on the outer surface of the tube. The ends of the tube near terminals are clamped in graphite jaws surrounded by a metal which is a good conductor and the tube is insulated with thermally stable material (I) between the graphite jaws. (I) being applied in such a way that its thickness increases from the middle to the ends of the tube. The length of the zone at constant temp. is increased considerably, since the higher energy losses due to conduction etc. away from the middle of the tube are compensated.