Solar Grade-Silicon, Ingot, Wafer Technology and ... - Displaybank
Solar Grade-Silicon, Ingot, Wafer Technology and ... - Displaybank
Solar Grade-Silicon, Ingot, Wafer Technology and ... - Displaybank
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<strong>Solar</strong> <strong>Grade</strong>-<strong>Silicon</strong>, <strong>Ingot</strong>, <strong>Wafer</strong> <strong>Technology</strong> <strong>and</strong> Market Trend (2008~2012)<br />
1.3. Poly-silicon Process<br />
The solar grade-silicon <strong>and</strong> its wafer manufacturing technology can be<br />
summarized like the figure below. The process starts with metallurgical silicon,<br />
MG-Si, which has about 99% purity <strong>and</strong> undergoes gasification <strong>and</strong><br />
purification processes to obtain silane gas. The silane gas is extracted at high<br />
temperature to obtain solar grade-silicon, SoG-Si. The solar grade-silicon<br />
manufacturing process includes Siemens, FBR, <strong>and</strong> VLD methods. Details of<br />
these methods will be discussed in the following chapter.<br />
Figure 1.3.1. <strong>Silicon</strong> <strong>Solar</strong> Cell Manufacturing Process<br />
SAMPLE<br />
The silicon obtained from the above process is categorized into chip (chunk),<br />
granular, <strong>and</strong> powder (dust-like) shapes upon the manufacturing method. The<br />
silicon is melt again to produce ingot. Czochralski, CZ, method is used to<br />
manufacture monocrystalline ingot <strong>and</strong> heating furnace is used to manufacture<br />
multicrystalline ingot blocks. The monocrystalline ingot has limited diameter<br />
since it grow crystal vertically <strong>and</strong> needs to cut edges to produce rectangular<br />
wafers that its final wafer size is smaller than the one of multicrystalline ingot<br />
method. Currently, the maximum size of the monocrystalline silicon wafer is<br />
156 x 156mm.<br />
The solar grade-silicon must satisfy physical property requirements like the<br />
following. First requirement is the size of poly-silicon. The size is an extremely<br />
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Jan’09