In today’s solar and semi-conductor silicon market all companies are looking for ways to reduce their production costs without sacrificing quality. The highest regular recurring maintenance costs in any CZ pulling operation are a result of the need to constantly replace the three piece or two piece graphite susceptor bowls.

In order to get the longest life and prevent unexpected silicon spills, graphite susceptor bowls are made from high density, fine grain, expensive isostatic graphite. During the crystal pulling process a combination of high temperature, low pressure and free silicon vapor cause a reaction between the silicon and the graphite susceptor converting the graphite to silicon carbide (SiC). As the reaction continues the SiC penetrates the graphite parts deeper and deeper.  Because SiC and the graphite have different coefficients of thermal expansion when the conversion reaches a certain depth the bowl will crack when rapidly heated and could cause a catastrophic failure of the unit due to molten silicon spillage.

Americarb has created a new process that can refurbish the bowls by reversing the reaction between the graphite and silicon and restore the original molecular structure of the bowl. After the refurbishing process, the bowls will not crack and can be put back into service for an additional service life equal to or exceeding a brand new bowl. Bowls must be removed from service before cracking occurs or they cannot be used. Graphite heaters can also benefit from the same process to extend the life of the components.