Industrial technology of multicrystalline silicon solar cells

This paper presents cut-rent technology used to produce 100 cm(2) multicrystalline silicon solar cells of efficiency above 13% which was one of the main goals of the National Photovoltaic Project undertaken in the Institute of Metallurgy and Materials Science (IMMS). The general concept of the technology consists of maximum seven steps. The process sequence is based on diffusion from POCl3 and screen printed contacts fired through a PECVD SixNy or TiOx antireflection coating (ARC). Co-metallisation annealing was performed in an IR furnace. The multicrystalline wafers are described using four-point probe, scanning electron microscopy (SEM), secondary ion mass spectrometer, and spectrophotometer with an integrating sphere. The completed solar cells are characterized with internal spectral response and a current-voltage characteristic. All aspects playing a role in a suitable manufacturing process are discussed. At present, multicrystalline silicon solar cells capture around a 45% share of the world photovoltaics market with a total of 540 MW being produced in 2002. Taking into account the decreasing cost of multicrystalline substrates, this relation will rise systematically.