Technical Papers and Notes - Institute of Metals Division - Determination of the Limiting Segregation of Gallium in Zone-Refined Germanium

ONE of the most important applications of the zone-melting process of Pfann1 concerns the refining of materials with respect to impurities whose distribution coefficient k differs from unity. The repeated passage of molten zones along an ingot concentrates the impurities for which k < 1, for example, towards the end to which the zones move. It is desirable to know the ultimate distribution of impurity after the passage of an infinite number of zones of constant length; this is also the distribution which is unchanged by the passage of a further molten zone.