Polycrystalline silicon, or multicrystalline silicon, also called polysilicon, poly-Si, or mc-Si, is a high purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry. Polysilicon is produced from metallurgical grade silicon by a chemical purification process, called the Siemens. In single-crystal silicon, also known as, the crystalline framework is homogeneous, which can be recognized by an even external colouring. The entire sample is one single, continuous and. Upgraded metallurgical-grade (UMG) silicon (also known as UMG-Si) for is being produced as a low cost alternative to polysilicon created by the. UMG-Si greatly reduces impurities in a variety of ways that require less equipment and. The use of polycrystalline silicon in the production of solar cells requires less material and therefore provides higher profits and increased manufacturing throughput. Polycrystalline silicon does not need to be deposited on a silicon wafer to form a solar cell, rather it. At the component level, polysilicon has long been used as the conducting gate material in and processing technologies. For these technologies it is deposited using low-pressure chemical-vapour deposition () reactors at high temperatures and is. Polysilicon deposition, or the process of depositing a layer of polycrystalline silicon on a semiconductor wafer, is achieved by the of (SiH4) at high temperatures of 580 to 650 °C. This process releases hydrogen. SiH 4(g) → Si(s) + 2 H. Currently, polysilicon is commonly used for the conducting gate materials in semiconductor devices such as ; however, it has potential for large-scale photovoltaic devices. The abundance, stability, and low toxicity of silicon, combined with the low. CapacityThe polysilicon manufacturing market is growing rapidly. According to, in July 2011, the total polysilicon production in 2010 was 209,000 tons. First-tier suppliers account for 64% of the market while China-based.