CPC Definition - Subclass C30B

Last Updated Version: 2023.02
SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J 3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H01L, H10); APPARATUS THEREFOR
Definition statement

This place covers:

Single crystals or homogeneous polycrystalline material with a defined structure; production thereof. Included in this subclass are processes and apparatus used in obtaining these crystals and materials. Also included in this subclass are processes and apparatus for the after-treatment of single crystals or homogeneous polycrystalline material with a defined structure.

When apparatus features do not correspond to any of the subgroup headings, they are classified in the head group. For example particle filtration means for a Czochralski apparatus: C30B 15/00.

References
Limiting references

This place does not cover:

Formation of diamonds using ultra-high pressure

B01J 3/06

Casting of metals, casting of other substances by the same processes or devices

B22D

Modifying the physical structure of metals or alloys

C21D, C22F

Zone-refining of metals or alloys

C22B

Production of semiconductor devices or parts thereof; semiconductor devices characterized by their crystalline structure or particular orientation of the crystalline planes

H01L, H10

Informative references

Attention is drawn to the following places, which may be of interest for search:

Separation by crystallisation in general

B01D 9/00

Metallic nanometer sized particles

B22F 1/054

Metallic nanotubes or nanofibres

B22F 1/0547

Grinding, polishing of crystals

B24B

Cleaving of stone or stone-like materials, e.g., brick, concrete, not provided for elsewhere

B28D 1/32

Mechanical fine working of gems, jewels, crystals

B28D 5/00

Working of plastics

B29

Coating by vacuum evaporation, by sputtering or by ion implantation of the coating material

C23C 14/00

Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating

C23C 16/00

Investigating or analysing biological crystals

G01N 33/48

Photonic crystals

G02B, G02F

Fabrication of semiconductor wafers

H01L 21/02

Special rules of classification
  • Reference B29 is non-limiting in the subclass C30B. CPC title will be updated/corrected once this inconsistency is resolved in IPC.
  • Patent and non-patent documents describing the growth of single crystals/homogenous polycrystalline material with defined structure are classified according to the method/apparatus used and the chemical and physical nature of the grown crystal.
  • Patent documents often list whole series of materials which can be grown as crystals. The classifier should provide the appropriate classification symbol under C30B 29/00 for those materials grown as crystals in the examples and any mentioned in the claims. Where a whole series is mentioned without emphasis on one particular material, for example GaAs, GaInAs, InAs, GaAlAs, GaN, InN, AlN etc., the classifier should try to identify the most appropriate classification(s) covering the families of materials mentioned. In this case C30B 29/40 and C30B 29/403 would be appropriate and suffcient.
  • Mere references to "crystals" or "single crystals" in a document in the absence of other details do not lead to a classification in C30B. For example a reference to a "Czochkralski grown silicon single crystal" in the description of a substrate used for a semiconductor device is not sufficient for requiring a classification in C30B. If, however, the reference includes further details about the chemical/physical properties of the crystal and these do not seem trivial then the classifier should give the appropriate C30B classification. Documents referring to the synthesis of chemical compounds which also mention crystallographic results for the solid are not normally classified in C30B unless there is emphasis on the crystal growing technique.
  • Concerning the circulation of documents to other fields by giving symbols of the other fields, most patents concerning crystal growth mention to different degrees of emphasis the applications where the grown crystal are to be used. Where there is a specific reference to a particular device or application using the crystal then the document should be circulated to that field. For example, a document mentioning the fabrication of a particular type of transistor using the grown crystal, then the document should be circulated to the semiconductor field (H01L).
  • Concerning vapour phase epitaxial growth apparatus, the search should always consult the relevant groups in C23C where such apparatuses are also classified. Epitaxial growth is dependent primarily on process parameters and substrate, an apparatus used for "epitaxial growth" in the overwhelming majority of cases the same apparatus can be used for providing non-epitaxial coatings. Documents concerning apparatus features in these processes should also be classified in C23C 14/00 and C23C 16/00.
Glossary of terms

In this place, the following terms or expressions are used with the meaning indicated:

Amorphous

Description of a solid material not having long-range crystalline lattice structure.

Crystal

Description of a solid material having long-range order of atoms or molecules arranged in a regularly-repeating lattice structure.

Defined structure

The structure of a solid material with grains which are oriented in a preferential way or have larger dimensions than normally obtained.

Epitaxy

The formation of a crystalline layer on a substrate in such a manner that the formed crystal bears a definite crystallographic relationship to the substrate.

Eutectic

Description of a mixture or solution containing two or more phases at a composition that has the lowest melting point and where the phases simultaneously crystallize from solution at this temperature.

Homogeneous polycrystalline material

A solid material with crystal particles, all of which have the same chemical composition.

Lattice

An ordered arrangement of atoms or molecules within a solid material.

Oriented crystalline material

A polycrystalline structure in which the grains are generally aligned in a preferential direction such as obtained in columnar growth.

Seed

A material, usually itself a small single-crystal, upon which a single-crystal is grown, the seeded crystal growth proceeding by the alignment of atoms or molecules or clusters into a thermodynamically favored arrangement determined by the nature of the seed.

Single-crystal

Description of a solid material having at least one long-range order of atoms or molecules in a regularly-repeating lattice structure throughout the body of material. Also includes twin crystals and a predominantly single crystal product.

Superlattice

A single-crystal having an internal structure of more than two layers, each layer having a composition different from the next adjacent layer.

Twin crystal

A crystalline material in which the adjoining crystalline lattices have a mirror-image symmetrical relationship, the interface between the adjoining crystals being termed the twin plane.

Zone melting

Description of a process in which a crystallized body is formed by melting a zone of a starting material with subsequent cooling and crystallisation while either the zone or the starting product is displaced so that all or part of the starting material is converted into the crystallized body.

Grains

Crystalline regions in a solid material, each grain generally being a single crystalline region.

Whiskers/needles

Discrete solid crystalline particles of generally elongated shape. Dimensions are superior to 100 nm and are not considered as nanocrystals (nanowires, nanorods etc.)

Bulk/layer

Bulk crystals have dimensions which are comparable in all three dimensions whereas layers have one dimension (thickness) significantly less then the other two dimensions (surface area). For thick layers the distinction may not be always evident and a certain degree of double classification is unavoidable. Often a bulk layer is grown from a discrete "seed" whereas a layer is grown epitaxially on a substrate.

Nanocrystals

Single crystals having at least one dimension less than 100 nm. The term includes nanowires, nanotubes, nanorods etc.

Synonyms and Keywords

In patent documents, the following abbreviations are often used:

SSR

Solid state re-crystallization

FZ

floating zone

SOI

silicon on insulator

SOS

silicon on sapphire

LHPG

laser heated pedestal growth

SLS

sequential lateral solidification

CZ or Cz

Czochralski

MCZ or MCz

Czochralski method with applied magnetic field

LEC

liquid encapsulated Czochralski

EFG

Edge defined film-fed growth

TSSG

Top-seeded solution growth

MBE

molecular beam epitaxy

PVD

physical vapour deposition

CVD

Chemical vapour deposition

MBA

molecular beam allotaxy

MCE

microchannel epitaxy

GSMBE

gas source molecular beam epitaxy

MOCVD

metalorganic chemical vapour deposition

OMVPE

organometallic vapour phase epitaxy

CBE

chemical beam epitaxy

HVPE

hydride vapour phase epitaxy

ALE

atomic layer epitaxy

MLE

molecular layer epitaxy

ELO/ELOG

epitaxial lateral overgrowth, pendeo epitaxy

Single-crystal growth directly from the solid state (unidirectional demixing of eutectoid materials C30B 3/00; under a protective fluid C30B 27/00)
Definition statement

This place covers:

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.

{Solid phase epitaxial growth through a disordered intermediate layer}
Definition statement

This place covers:

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.

Unidirectional demixing of eutectoid materials
Definition statement

This place covers:

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.

Single-crystal growth from gels (under a protective fluid C30B 27/00)
Definition statement

This place covers:

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.

References
Limiting references

This place does not cover:

Macroscale photonic band gap crystals

G02B 6/1225

Single-crystal growth from melt solutions using molten solvents (by normal or gradient freezing C30B 11/00; by zone-melting C30B 13/00; by crystal pulling C30B 15/00; on immersed seed crystal C30B 17/00; by liquid phase epitaxial growth C30B 19/00; under a protective fluid C30B 27/00)
Definition statement

This place covers:

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.

by induction, e.g. hot wire technique (C30B 13/18 takes precedence)
References
Limiting references

This place does not cover:

The heating element being in contact with, or immersed in, the molten zone

C30B 13/18

Informative references

Attention is drawn to the following places, which may be of interest for search:

Induction coils

H05B 6/36

Controlling or regulating
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Controlling or regulating in general

G05

Single-crystal growth by condensing evaporated or sublimed materials
Definition statement

This place covers:

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

Epitaxial-layer growth
Definition statement

This place covers:

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

References
Limiting references

This place does not cover:

Physical vapour deposition wherein generally unstructured polycrystalline or amorphous coatings are produced.

C23C 14/00 and sub-groups

Informative references

Attention is drawn to the following places, which may be of interest for search:

General apparatus features

C23C 14/00 and subgroups pertaining to apparatus features, e.g. C23C 14/50: substrate holders

Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
Definition statement

This place covers:

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

Epitaxial-layer growth
Definition statement

This place covers:

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.

References
Limiting references

This place does not cover:

Production of polycrystalline products such as silicon and germanium by the so-called Siemen's process from the vapour phase

C01B 33/035

Chemical vapour deposition wherein generally unstructured polycrystalline or amorphous coatings are produced

C23C 16/00 and sub-groups

Informative references

Attention is drawn to the following places, which may be of interest for search:

CVD apparatus features

C23C 16/00 and sub-groups pertaining to apparatus features

{by irradiation or electric discharge}
Definition statement

This place covers:

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.

Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
Definition statement

This place covers:

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

References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Alloys

C22C

Elements
Definition statement

This place covers:

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

References
Limiting references

This place does not cover:

Fullerene

C01B 32/152

Graphene

C01B 32/182

Nitrides
References
Limiting references

This place does not cover:

AIII-nitrides (including born nitride)

C30B 29/403, C30B 29/406

Macromolecular compounds
Definition statement

This place covers:

Macromolecular compounds including biological compounds such as proteins and enzymes.

characterised by shape
Definition statement

This place covers:

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

{Nanotubes}
References
Limiting references

This place does not cover:

CNT carbon nanotubes

C01B 32/158

{Products containing multiple oriented crystallites, e.g. columnar crystallites}
Definition statement

This place covers:

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

Diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure; Apparatus therefor
Relationships with other classification places

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

Controlling or regulating
References
Informative references

Attention is drawn to the following places, which may be of interest for search:

Controlling or regulating in general

G05

After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B 31/00 takes precedence)
References
Limiting references

This place does not cover:

Diffusion or doping processes for single crystals or homogeneous polycrystalline material with defined structure; Apparatus therefor

C30B 31/00

Informative references

Attention is drawn to the following places, which may be of interest for search:

Grinding, polishing

B24

Mechanical fine working of gems, jewels, crystals

B28D 5/00

{Apparatus for preparing, pre-treating the source material to be used for crystal growth}
Definition statement

This place covers:

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