20.10.2018 Views

knjiga solarna energija dobra

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

BULK MULTICRYSTALLINE SILICON 215<br />

Inductive heating<br />

Liquid<br />

silicon<br />

Directionally solidified<br />

silicon<br />

Solid−liquid<br />

interface<br />

Figure 6.6 Conventional Bridgman technique that still is mainly used for the fabrication of multicrystalline<br />

ingots. Both melting and crystallisation of the silicon is performed in a Si 3 N 4 -coated<br />

quartz crucible. Crystallisation is realised by slowly moving downward the liquid silicon-containing<br />

crucible out of the inductively heated hot zone of the process chamber<br />

Solid−liquid<br />

interface<br />

Directionally solidified<br />

silicon<br />

Inductive heating<br />

Liquid silicon<br />

Casting<br />

Crystallization<br />

Figure 6.7 Block-casting process for the fabrication of multicrystalline silicon. After melting the<br />

silicon in a quartz pot, the silicon is poured into a second quartz crucible with a Si 3 N 4 coating. The<br />

heating elements of the crystallisation crucible are not shown in the figure. In comparison with the<br />

Bridgman technique (see Figure 6.6), shorter crystallisation and cooling times can be realised by<br />

employing a more variable heater system

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!