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1、晶体生长计算软件FEMAG之晶体生长方法汇编,Bulk Crystals Materials,FEMAGSoft 2010,Whole industries rely on bulk-grown crystals of a variety of materials,Silcion/Germanium for semiconductor and solar industryIII-V compunds(GaAs Inp InSb SiC GaN etc)for telecommication,LED,defense and solar industryHgCdTe for infrared im
2、aging Fluoride/Halide/oxide scintillator crystals for high-energy physics,medical imaging and optical industriesetc.,Bulk Crystal Growth Methods,FEMAGSoft 2010,Czochralski(CZ)Floating Zone(FZ)Directional Solidification(DSS)Vertical/Horizontal Bridgman(VB)Vertical Gradient freeze(VGF)Physical Vapor T
3、ransport(PVT),Silicon Crystal Growth Method,FEMAGSoft 2010,String Ribbon(Patented by EVERGREEN)EFG,Hotzone importance,FEMAGSoft 2010,The key important thing for all growth processes is the Hotzone and associated operating condtions,which control the major characterstics of crystals,and the structure
4、 of the hotzone and associated operating conditions are the major know-how of each IC wafer manufacturers.,Czochralski Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Czochralski Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Czochralski Method,Around 90%single crystal grown by Cz method in IC industryPart
5、 of Germanium crystal grown by CZ methodSappher and lots Compound crystal grown by CZ or its variants,such as Kyropoulos,LEC etc.Market share of CZ wafer in solar market slightly lower than DSS mc wafer,Czochralski Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Hot topics once in IC industry,and curren
6、tly hot topics for solar:all about growth yield,and then quality improvement,CCZ with multi-melt partitionsMCZGrowth rate improvement,Impurity control(oxygen,carbon)and dopants microvoids and dislocations on cell efficiency,Czochralski Growth Method(MCZ),FEMAGSoft 2010,FEMAGSoft 2006,Cost reduction
7、is limited with respected to the equipments/consumables modificationsInnotative efforts are required to further be improved,Czochralski Growth Method(MCZ),FEMAGSoft 2010,FEMAGSoft 2006,Vertical:Cusp:Horizontal:,FEMAGSoft 2006,Czochralski Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,It is assumed that
8、 for a certain region of the thermal stresses the crystal is in a metastable state,and a certain perturbation energy is necessary to leave this metastable state.By this model,it can be understood that the crystal can bear higher stresses than the critical values determined by a tensile test.Conformi
9、ng to the classical idea of dislocation generation it starts somewhere near the growth interface,where the highest stresses are located and then grows deeper into the crystal.At these points of high stress level,the dislocation process may be started due to a perturbation energy resulting from:-temp
10、erature fluctuations(hydrodynamic and/or growth system instabilities)-local back melting-particles reaching the growth interface.,Structure lose currently is the main issue on growth yield,Floating Zone Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Mainly for high-power devicesWorld-record cell effici
11、ency is basedToo expensive due to equipment and feedstock,DSS Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,DSS Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Manufacturers are benefiting from efforts did on CZ/VGF process for IC in past years.,DSS Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Major issues
12、 for DSS growth process:,Growth yield improvementGrain-size control and improvementDopant/Impurities(C/N)distributionDislocation,Growth rateHeater power distribution,Not key issues for DSS growth process:,Cost is only 1/3 or CZ process,more than 50%market shareLow oxygen concentrationLow requirement
13、s of silicon feedstock,Hot topics for DSS Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Continuous feeding:same as CCZ,the pontential for cost reduction is limited:,Requirement of additonal feeding systemRequirement of small-size or even silicon powder feedstock,Monocrystalline casting:,CZ-like qualit
14、y but with DSS cost,then huge cost reductionNo additional investment on equipmentHotzone design(temperature profile near seed and heater power distribution),Leaders are BP Solar,GT Solar and Chinese companies.,Hot topics for DSS Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,Hot topics for DSS Growth M
15、ethod,FEMAGSoft 2010,FEMAGSoft 2006,Facts about mono-ingot by DSS:1)The cell efficiency of good qulaity mono-wafer by DSS is very close to mono-wafer by CZ(18.8%from GT)2)On average,the difference between mono CZ and DSS is only 0.5%1%difference,and 1%higher than traditional DSS multi-wafer.3)Overall production cost is only 1/3 of CZ,but with mono quality.4)Lower LID effect,low feedstock requirements and higher yield.,VB Growth Method,FEMAGSoft 2010,FEMAGSoft 2006,VB is widely used to grow Si/Ge and compound crystals:（待续）,
