The contamination from an inert crucible or boat in a flow of H2 : here the Si
incorporation into the Ga liquid becomes significant only at larger temperatures
(> 800°C) and in a very dry H2 flow over long periods. Weiner's calculations
were based on local thermodynamic equilibrium when the initial pressure of
water (PH2O˚) in the system, including any water from reaction between H2 and
O2, is increased. He found that the rate of contamination depends only slightly
on PH2O˚ but 2 when the PH2O˚ is increased by the introduction of O2 then the rate
of Si contamination drops rapidly; this is because a significant fraction of total