in the gaseous or vapour state

Full Title

Single-crystal growth by zone-melting; Refining by zone-melting (C30B17/00 takes precedence; by changing the cross-section of the treated solid C30B15/00; under a protective fluid C30B27/00; for the growth of homogeneous polycrystalline material with defined structure C30B28/00) > adding crystallising materials or reactants forming it in situ to the molten zone > with addition of doping materials > in the gaseous or vapour state