Optical in-situ measurement of the dissolution rate of a silica-Czochralski-crucible with silicon melt and comparison to ex-situ measurements

Abstract

The dissolution of the silica crucible by the silicon melt acts as a source of oxygen doping in the growth of silicon single crystals by the Czochralski-method. Literature data on the dissolution rate of silica in silicon melts are available up to now only from ex-situ measurements. These data were obtained by measuring the decrease of the diameter of silica rods or plates dipped into a silicon melt. In the present work, the silica dissolution rate is measured for the first time by an in-situ technique. The decrease of the thickness of the wall of a silica crucible of a laboratory-scale Czochralski crucible containing silicon melt is measured by optical laser interferometry. The obtained results are compared quantitatively to literature data obtained by the above-mentioned ex-situ technique.