The atoms and molecules of the precipitation matter collide from the gas phase state to the crystal surface and are adsorbed by the crystal to grow a crystal. There are a lot of variables in the growth from vapour phase process, which makes the growth process more difficult to control, so growth from vapour phase is often limited to materials that are difficult to grow from crystal growth from liquid phase. One of the characteristics of growth from vapour phase is that the equilibrium constant of the proposed reaction and its temperature dependence can often be determined in advance. Its most important application is epitaxial growth on homogeneous and heterogeneous materials substrates. This method has become the basic method for manufacturing many semiconductors, optoelectronic devices, and acoustooptic devices. It is of great significance in industry, and growth from vapour phase must have several necessary conditions: ① the vapor pressure on the crystal is higher than the equilibrium vapor pressure; ② The environment around the crystal should be conducive to surface diffusion; ③ The surrounding environment of the substrate should be conducive to the development of crystal. The material transport mode in growth from vapour phase can be physical (the high temperature part is transported to the low temperature area through air flow and precipitation) and chemical (the steam precipitation is provided on the crystal by chemical reaction) "growth from vapour phase can be divided into single component system and multi-component system in terms of composition. Single component growth from vapour phase includes sublimation method method, sputtering method and ion implantation method. crystal grown by single component system include SiC, CdS, ZnS, etc., and crystal are mostly needle shaped or sheet shaped. Multicomponent systems are commonly used for epitaxial growth, which can be divided into reversible reactive growth and irreversible reactive growth. GaAs, GaAs. rP ^, GaP and other epitaxial films are commonly produced by this method Long.
Inorganic non-metallic materials -> Crystal growth and crystal materials