automatic generation of Cz geometries

CrysMAS comes with a tool to automatically generate files for the simulation of different growth stages of a Cz process, called GenerateCzGeometry. The initial input for this tool is a crys-file describing a model of the Cz furnace without melt or crystal, as shown below.

Input for Cz geometry generator 

Model without melt and crystals, labels for crucible, cruciblesupport, cruciblerod

Figure 117. Input for Cz geometry generator

Using the labels dialog (Settings -> labels), you have to assign predefined labels to regions in the model:

The generator tool then requires a test input file containing the following key - value pairs, strictly in the given order:

Parameter

example Value

Meaning

casename

CzExample

case name of input crys-file (without melt or crystal)

capillaryConstant

0.0076

capillarity constant (here for Silicon), used in estimation of meniscus shape

growthAngle

12

angle between growing crystal and meniscus, 11 or 12 degree is frequently given for Silicon

meltmaterial

Silizium

two-phase material used for crystal/melt, must be present in materials dialog

initialmass

120

total initial mass of e.g. silicon, in kg.

restmass

5

mass of melt remaining in crucible when the crystal is pulled out

crystalRadius

0.105

radius of cylindrical part of crystal, in m.

crystalMass

60

mass of crystal - for this parameter, there may be several lines, one for each crystal mass to be generated

meltSurfHeight

1.2717

axial (z) - position of melt surface: for different crystal masses, the crucible and crucible support will be moved such that the surface of the melt is always at the given position

seedRadius

0.002

radius of the seed which will be created

seedLength

0.1

length of the seed which will be created

startConeAngle

5

shoulder angle, in degree

startConeAngle

30

end cone angle, in degree

numSegments

10

number of line segments forming the meniscus shape

mindz

0.0001

In the approximation used, the meniscus extends into infinity. Meniscus height is set to 0 (above melt surface), when it becomes smaller than the value given here

An example input file (CzExample_geom_in) and crys-file (CzExample.crys) can be found in the tutorial files, the results produced by running GenerateCzGeometry on these files are shown below.

Output generated by GenerateCzGeometry for crystal masses of 1, 60 and 110kg for model shown above 

Figure 118. Output generated by GenerateCzGeometry for crystal masses of 1, 60 and 110kg for model shown above