Recrystallization of silicon polygonal tubes using an electric closed molten zone

Abstract

This article describes a process for generating and controlling a closed molten zone with an induced electrical current, and using it for silicon ribbon tube recrystallization. The silicon tube is the secondary loop of a transformer in which the current is generated by electrical induction. The Joule heat caused by the induced current generates a closed molten line along a cross section of the silicon tube; scanning this molten zone along the tube axis results in material recrystallization, with no contact with foreign materials. From the recrystallized silicon tube faces test solar cells were produced, revealing minority carrier diffusion lengths around 100 μm.