Single crystals or homogeneous polycrystalline material with a defined structure; production thereof.

Processes and apparatus used in obtaining these crystals and materials.

Processes and apparatus for the after-treatment of single crystals or homogeneous polycrystalline material with a defined structure.

Where there is a specific reference to a particular device or application using the crystal then the document should be classified in that field. For example, a document mentioning the fabrication of a particular type of transistor using the grown crystal, then the document should be classified in the semiconductor devices, i.e. subclass H01L.

Vapour phase epitaxial growth apparatus is similar to apparatus used for providing non-epitaxial coatings. Therefore, documents concerning apparatus features in these processes should also be classified in C23C 14/00 and C23C 16/00.

Reference B29 is non-limiting in the subclass C30B. CPC will be updated/corrected once this inconsistency is resolved in IPC.

Looping references between C30B and C21D have been identified. Until this inconsistency is resolved in IPC, the current classification practice in CPC is as follows: C30B and C21D are considered as informative reference.

The preparation of single crystals or a homogeneous polycrystalline material with defined structure of particular materials or shapes is classified in the group for the process as well as in group C30B 29/00.

Where a whole series is mentioned without emphasis on one particular material, for example GaAs, GaInAs, InAs, GaAlAs, GaN, InN, AlN, etc., it is classified in the groups covering the families of materials mentioned, in this case C30B 29/40 and C30B 29/403.

An apparatus specially adapted for a specific process in classified in the appropriate group for the process. Apparatus to be used in more than one kind of process is classified in group C30B 35/00.

Particular attention is paid to documents where crystal growth is induced by e.g. scanning zones of a material to be crystallized with e.g. a laser beam. If the material to be crystallized becomes molten prior to cooling and crystallization then the document is not classified here but is allocated a classification under C30B 13/00.

Growth methods where for example the crystallographic structure of a substrate is transferred via e.g. an intermediate amorphous layer to an overlying layer during a heat treatment below the melting point of the different layers.

Method (and specific apparatus) for the growth of single crystals and homogenous polycrystalline materials from a eutectic mixture wherein on a unidrectional cooling a distinct composite structure forms. For example, aligned fibres of one phase form in a matrix of another phase when a eutectic mixture is directionally cooled. This transformation or demixing may occur when the material is cooled from the solid state. Most frequently this growth method concerns metallic eutectic alloys. This group has not been frequently used in recent years.

Growth from colloidal systems is also classified here. Growth of larger crystals from ordering of macromolecules can be classified here. Periodic 2D and 3D structures formed by self assembly from colloidal systems of particles/nanospheres/microspheres to form photonic "crystals" have been classified here. This is subject to some discussion. In principle 2D or 3D structures called "photonic crystals" but made by the assembly of macroscale structures are not classified in C30B.

The growth of bulk crystal are classified here whereas epitaxial layer growth from the melt (with and without solvents/flux) are classified in C30B 19/00. Some double classification is unavoidable.

The growth of bulk crystals, as opposed to layers, from vapours produced by physical processes such as sublimation is classified here.

Epitaxial layer growth from vapours produced by physical processes, e.g. molecular beam epitaxy (MBE), sputtering, sublimation etc.

The growth of bulk crystals by chemical vapour phase deposition (CVD, MOCVD etc) is classified here.

Epitaxial layer growth by chemical vapour phase deposition (CVD,MOCVD,MOVPE, HVPE etc). Also classified here is gas source molecular beam epitaxy (GSMBE) wherein a hybrid process CVD-MBE is involved.

Heating by irradiation or electric discharge includes plasma assisted methods C30B 28/00

classified here are documents in which there is a particular emphasis on a feature relating to the polycrystallinity of the product (grain size, orientation). Crystal growing methods and apparatus should receive the usual classifications irrespective of whether polycrystalline, multi-crystalline or monocrystalline products are formed.

Classified here are single crystals or homogenous polycrystalline material with defined structure according to their chemical composition or shape.

In addition to other elements, non-diamond forms of carbon are classified here.

Macromolecular compounds including biological compounds such as proteins and enzymes.

Classified here are discrete single crystals characterized by shape as opposed to products containing multiple oriented crystalline material (C30B 29/605).

Also nanomaterials, nanocrystalline materials which have a uniform i.e. homogeneous, oriented structure

Apparatus for diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure can also be classified in C23C if the apparatus is used for surface treatment of metallic material by diffusion into the surface or for coating metallic material

This group also covers methods for preparing , pre-treating the source material to be used for crystal growth.