Silicon is the most common element in the earth’s crust after oxygen and is commonly found in the form of silicon dioxide or its more common name of quartz. Quartz is made up of silicon and oxygen. To release the silicon, the oxygen must be removed from the Quartzite at high temperatures.
Metallurgical grade silicon (MG-Si) is used to make solar grade polysilicon. The MG-SI is prepared by combining silicon with wood, charcoal and coal, in an electric arc furnace using carbon electrodes. At temperatures over 1,900 °C (3,450 °F), the carbon reduces the silica to liquid silicon which collects in the bottom of the furnace, and is then drained and cooled to form MG-Si.
High quality Trichlorosilane Gas (TCS) is fed into a reactor with hydrogen where it solidifies on heated U shaped rods to form polysilicon. This is called the Siemens process. Once the U rods are cooled the polysilicon can be collected and transformed into a more usable format.
Polysilicon is melted down and reshaped to make either monocrystaline or multicrystaline ingots. These ingots vary in size and length.
Monocrystalline and mutlicrystalline ingots are often reshaped according to their desired usage before being sliced by a wire saw into ultrathin wafers. Wafers then have other chemicals added to enhance their efficiency in a process called doping, and are then cleaned to remove any unwanted particles.
Solar Cells are made from wafers and convert the energy from sunlight into electricity in what is known as the photovoltaic effect. Solar cells are the building blocks of solar modules.
Solar modules (also known as solar panels) are comprised of interconnected clusters of solar cells. These cells are generally protected by an aluminium housing and glass.
Modules are installed in singularly or together in arrays for a wide range of residential and commercial power generation applications.