Publication date: 15 February 2017
Source:Journal of Crystal Growth, Volume 460
Author(s): M. Porrini, R. Scala, V.V. Voronkov
The evaporation from the silicon melt, during Czochralski process, is an important effect for Phosphorus and Antimony dopants. The evaporation rate γ was deduced from the measured axial profile of the resistivity converted into the concentration. For the heavily doped crystals, the value of γ is very similar for both P and Sb: in the order of 5.5×10−5 cm/s (which is significantly lower than the previously reported evaporation rates). It was concluded that the rate-limiting step for the evaporation process is neither the evaporation reaction itself nor the impurity transport through the flowing gas, but rather the transport through the melt that strongly depends on the melt convection. For low Phosphorus concentration, the transport through the gas is severely slowed-down – due to a change in the dominant gaseous species, from P2 to P1 – and becomes a limiting step. The evaporation rate is decreased and, in fact, becomes negligible.
Source:Journal of Crystal Growth, Volume 460
Author(s): M. Porrini, R. Scala, V.V. Voronkov