DORFNER Analysenzentrum und Anlagenplanungsgesellschaft mbH
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Solar, Silicon

Solar Silicon

Today, most solar grade silicon (SoG-Si) production follows the SIEMENS Process and its derivatives. This provides highest purity but it is a high energy consuming process resulting in prices as high as 40 EUR/kg.

But, the quality requirements for solar grade silicon are less than high-end microelectronics grade silicon (ME-Si). To meet the specifications required by the photovoltaic (PV) industry, alternative production technologies arise on a much lower investment and process cost base by using quartz of sufficient purity and carbon.

New opportunities developed via direct carbothermic reduction or refinement of metallurgical grade silicon (UMG‑Si) need to avoid certain metal impurities as well as phosphorus and boron in the raw material. Since carbon mainly derives from synthetic processes the source of most of the impurities is the raw quartz. In order to control the purity of the silicon, the quality and refining processes of the raw quartz are crucial to comply with PV industry standards.