The parent patent describes crucible-free zone-melting appts. in which the conical bottom end of a vertical semi-conductor crystal rod is attached to a seed crystal. The conical end of the rod is supported by a set of arms coupled to, but able to move axially w.r.t., the seed holder. Improvement is that the seed holder is rigidly fixed to a plate fitted with =3 pivot mountings each carrying a lever arm (a); and a ring can be moved vertically round the seed holder to bring the three arms (a) in contact with the conical end of the crystal rod. The top of each arm (a) has an inert peg with an adhesive or melting contact substance (b). Contacts (b) are pref. pellets of AgCl, AgI, CuCl, or solid alkali hydroxide; and are located on pegs of Si or SiO2 on arms (a) made of light metal sheet. Used to prevent vibration of the bottom end of the crystal rod which might otherwise stop the process.
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