Chemical Vapour Deposition Method for Preparation Crystal - QS Study
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Chemical Vapour Deposition (CVD) method: This method is based on the crystallization of reactants in the vapour or gas phase. In this method volatile starting materials are mixed at a suitable temperature and the solid products are crystallized out. Sometime the volatile compounds are passed through the reaction vessels with an inert carrier gas. Typical volatile materials include among others, hydrides, halides, organo-metallic compounds etc.

Semiconductors by Chemical Vapor Deposition

AsCl3 + Ga + 3/2 H2 → GaAs + 3 HCl

SiCl4 + 2 H2 → Si + 4 HCl

SiH4 → Si + 2 H2

Diamond Films

  • Diamond films are made by CVD at low pressure and below 1300 K by heating gas mixtures (methane or acetylene and hydrogen), or by breaking down the mixtures with microwaves.
  • The carbon atoms and carbon containing radicals are deposited onto a substrate.
  • It is also possible to deposit monocrystalline layers onto a seed diamond, building a larger diamond layer by layer.