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Encyclopedia > Czochralski process

The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and some man made, (or "lab") gemstones. Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... A single crystal is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample. ... A semiconductor is a material that is an insulator at very low temperature, but which has a sizable electrical conductivity at room temperature. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... This article is about the chemical compound. ... General Name, Symbol, Number palladium, Pd, 46 Chemical series transition metals Group, Period, Block 10, 5, d Appearance silvery white metallic Atomic mass 106. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... General Name, Symbol, Number silver, Ag, 47 Chemical series transition metals Group, Period, Block 11, 5, d Appearance lustrous white metal Atomic mass 107. ... General Name, Symbol, Number gold, Au, 79 Chemical series transition metals Group, Period, Block 11, 6, d Appearance metallic yellow Atomic mass 196. ... A selection of gemstone pebbles made by tumbling rough rock with abrasive grit, in a rotating drum. ...

Crucibles used in Czochralski method
Crucibles used in Czochralski method

The most important application may be the growth of large cylindrical ingots, or boules, of single crystal silicon. High-purity, semiconductor-grade silicon (only a few parts per million of impurities) is melted down in a crucible , which is usually made of Quartz. Dopant impurity atoms such as boron or phosphorus can be added to the molten intrinsic silicon in precise amounts in order to dope the silicon, thus changing it into n-type or p-type extrinsic silicon. This influences the electrical conductivity of the silicon. A seed crystal, mounted on a rod, is dipped into the molten silicon. The seed crystal's rod is pulled upwards and rotated at the same time. By precisely controlling the temperature gradients, rate of pulling and speed of rotation, it is possible to extract a large, single-crystal, cylindrical ingot from the melt. This process is normally performed in an inert atmosphere, such as argon, and in an inert chamber, such as quartz. ImageMetadata File history File links Download high resolution version (2048x1536, 604 KB) Summary Title: Crucibles used in Czochralski method Desc: Two unused crucibles - smaller one is placed in the big crucible, which is not the case during the crystal growth process. ... ImageMetadata File history File links Download high resolution version (2048x1536, 604 KB) Summary Title: Crucibles used in Czochralski method Desc: Two unused crucibles - smaller one is placed in the big crucible, which is not the case during the crystal growth process. ... An ingot is a mass of metal or semiconducting material, heated past the melting point, and then recast, typically into the form of a bar or block. ... A boule is a term used to describe a single crystal ingot produced by synthetic means. ... A single crystal is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... A semiconductor is a material with an electrical conductivity that is intermediate between that of an insulator and a conductor. ... For other uses of crucible, see Crucible (disambiguation) Categories: Alchemical apparatus ... Quartz is the most abundant mineral in the Earths continental crust. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Atomic mass 10. ... This article is about the chemical element. ... Electrical conduction is an electrical phenomenon where a material (solid or otherwise) contains movable particles with electric charge, which can carry electricity. ... A seed crystal is a small piece of single crystal material from which a large crystal of, usually, the same material is to be grown. ... In English, to be inert is to be in a state of doing little or nothing. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... Quartz is the most abundant mineral in the Earths continental crust. ...

 Crucible after being used
Crucible after being used

Image:Czochralski Process.png ImageMetadata File history File links Download high resolution version (1536x2048, 904 KB) Summary Title: Crucible used in Czochralski method Desc: This crucible was used to pull a silicon crystal by Czochralski method. ... ImageMetadata File history File links Download high resolution version (1536x2048, 904 KB) Summary Title: Crucible used in Czochralski method Desc: This crucible was used to pull a silicon crystal by Czochralski method. ... Image File history File links Czochralski_Process. ...

Silicon wafer with mirror finish (NASA)
Silicon wafer with mirror finish (NASA)

While the largest silicon ingots produced today are 400 mm in diameter and 1 to 2 metres in length, 200 mm and 300 mm diameter crystals are standard industrial processes. Thin silicon wafers are cut from these ingots (typically about 0.75 mm thick) and polished to a very high flatness to be used for creating integrated circuits. Other semiconductors, such as gallium arsenide, can also be grown by this method, although lower defect densities in this case can be obtained using variants of the Bridgeman technique. Image File history File links Date: 02. ... Image File history File links Date: 02. ... NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... An etched silicon wafer In microelectronics, a wafer is a thin slice of semiconducting material, such as a silicon crystal, upon which microcircuits are constructed by doping (for example, diffusion or ion implantation), etching, and deposition of various materials. ... SEM image of an integrated circuit showing defects in the aluminium layer deposition (shown in cyan). ... This article is about the chemical compound. ... The Bridgeman technique is a method of growing single crystal ingots or boules. ...


When silicon is grown by the Czochralski method the melt is contained in a silica (quartz) crucible. During growth the walls of the crucible dissolve into the melt and Czochralski silicon therefore contains oxygen impurities with a typical concentration of 1018cm − 3. Perhaps surprisingly, oxygen impurities can have beneficial effects. Carefully chosen annealing conditions can allow the formation of oxygen precipitates. These have the effect of trapping unwanted transition metal impurities in a process known as gettering. Additionally, oxygen impurities can improve the mechanical strength of silicon wafers by immobilising any dislocations which may be introduced during device processing. It has experimentally been proved in the 1990s that the high oxygen concentration is also beneficial for radiation hardness of silicon particle detectors used in harsh radiation environment ( eg. CERN's LHC/S-LHC projects)[1,2,3]. Therefore, radiation detectors made of Czochralski- and Magnetic Czochralski-silicon are considered to be promising candidates for many future High Energy Physics experiments [5,6]. The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Quartz is the most abundant mineral in the Earths continental crust. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc and scandium. ... To prevent any remaining gases from remaining in a free state in a vacuum tube, modern tubes are constructed with getters, which are usually small, circular troughs filled with metals that oxidize quickly, with barium being the most common. ... For the syntaxic operation, see Dislocation (syntax) For the medical term, see Dislocation (medicine) In materials science a dislocation is a linear crystallographic defect, or irregularity, in crystal structure. ... CERN logo CERN is the Organisation Européenne pour la Recherche Nucléaire (European Organization for Nuclear Research ), the worlds largest particle physics laboratory, situated on the border between France and Switzerland, just west of Geneva. ... For the pop group, see Les Horribles Cernettes Construction of the CMS detector for LHC at CERN The Large Hadron Collider (short LHC) is a particle accelerator and collider located at CERN. It is currently under construction and scheduled to start operation in 2007. ...


Occurrence of unwanted instabilities in the melt can be avoided by investigating and visualizing the temperature and velocity fields during the crystal growth process [4].


The process is named after Jan Czochralski, who discovered the method in 1916 while investigating the crystallization rates of metals. Jan Czochralski (pronounced cho-HRAL-skee) (October 23, 1885 - April 22, 1953) was a Polish chemist who discovered the Czochralski process, which is used to grow single crystals and is used in the production of semiconductor wafers. ... 1916 (MCMXVI) is a leap year starting on Saturday (link will take you to calendar) // Events January-February January 1 - The Royal Army Medical Corps first successful blood transfusion using blood that had been stored and cooled. ...


References


[1] Z. Li et al., IEEE Trans Nucl. Sci. 39 (6) (1992) 1730.


[2] A. Ruzin et al., IEEE Trans Nucl. Sci. 46 (5) (1999) 1310.


[3] G. Lindström et al., Nucl. Instr. and Meth. A 466 (2001) 308 and cited literature therein.


[4] J. Aleksic et al., Ann. of NY Academy of Sci. 972 (2002) 158.


[5] CERN RD50 Status Report 2004, CERN-LHCC-2004-031 and LHCC-RD-005 and cited literature therein.


[6] J. Härkönen et al., Nucl. Instr. and Meth. A 541 (2005)202.


  Results from FactBites:
 
Czochralski process - Wikipedia, the free encyclopedia (532 words)
The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e.g.
This process is normally performed in an inert atmosphere, such as argon, and in an inert chamber, such as quartz.
The process is named after Jan Czochralski, who discovered the method in 1916 while investigating the crystallization rates of metals.
  More results at FactBites »

 
 

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