Monocrystals prodn. in closed horizontal system - using seed fitted lightly in flat-ended boat, preventing seed migration

摘要

In the prodn. of monocrystals, esp. AIIIBV monocrystals in the horizontal closed system, using a monocrystalline seed with definite crystallographic orientation, at reduced and elevated pressure, the seed crystal is fitted tightly in a boat having a flat wall, perpendicular to the axis of the boat, at the end next to the seed. The seed pref. is fitted in the boat so that the capillary gap between the seed and the wall of the boat is max. 300 mu. The boat pref. widens conically from this end for a certain length and then is of constant width, the conical part pref. being 10-100 mm long and increasing the cross-section of the seed up to a factor of 150. Method is esp. for the prodn. of GaAs and GaP monocrystals for luminescent diodes. The boat prevents the seed moving and gives a sharp monocrystalline solid/liquid phase boundary.