Controlled directional solidification of silicon

Abstract

The present invention relates to apparatus and methods for directionally solidifying silicon. The apparatus may use a cooling platform to cool a portion of the bottom of the directional solidification crucible. The apparatus and method of the present invention can be used to manufacture silicon crystals for use in solar cells.

Description

[0001] related application [0002] This application claims priority to US Provisional Application No. 61 / 663,940, filed June 25, 2012, which is hereby incorporated by reference in its entirety. Background technique [0003] Solar cells are a viable energy source by harnessing their ability to convert sunlight into electricity. Silicon is a semiconductor material used in the manufacture of solar cells; however, limitations on the use of silicon relate to the cost of purifying it to solar grade (SG). [0004] Several techniques are known for preparing silicon crystals for solar cells. Most of these techniques operate on the principle that when silicon solidifies from a molten solution, undesired impurities tend to remain in the molten solution. For example, float zone technology can be used to create monocrystalline ingots and use moving liquid regions within a solid material to move impurities to the edge of the material. In another example, the Czochralski technique can b...

AI Technical Summary

Problems solved by technology

Such temperature control mechanisms can involve relatively expensive and difficult to maintain cooling or heating conduits within the directional solidification crucible

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