Quantitative optical in-situ measurement of the dissolution rate of the silica crucible in the silicon Czochralski process

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. 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 quantitatively by optical laser interferometry. It is demonstrated that the influence of relevant growth parameters of the silicon Czochralski process like temperature of the silica crucible wall and pressure of the Argon gas can be detected and quantitatively related to the dissolution rate.