Making of Mono or Poly Crystalline Cells
Making of Mono or Poly Crystalline Cell
(1) First, silicon is extracted from silica sand or silicon dioxide, which is usually made from crushed quartz rock.
(2) The silica sand must then be purified using a process called Carbon Arc Welding (CAW) which extracts the unwanted oxygen and results in 99% pure silica.
(3) The silica is then further processed to become as close to 100% pure silicon.
(4) The end result is very pure polycrystalline silicon which can be doped with trace amounts of either boron or phosphorous to become either P-type or N-type silicon.
(5) At this stage the polycrystalline silicon can be melted and cast into a large rectangular blocks and thinly sliced using a diamond wire cutting method to produce the polycrystalline or multicrystalline wafers.
(6) At last, from polycrystalline or multicrystalline wafers, polycrystalline or multicrystalline cells are made.