Rear-surface passivation and design for thin p-type multicrystalline silicon solar cells

Recently, an important trend within crystalline silicon solar cell processing is the assignment of a more prominent role to thin (≤150 μm) substrates. This considerably reduces dominant material costs, albeit at the expense of giving up well-established solar cell processing steps, such as the screen printed aluminium back-surface-field an contact formation, due to excessive warping of the cells. Next to this, trinner wafers evidently increase the need for excellent rear-surface passivation-schemes. Finally, it is generally accepted that when using multicrystalline Si substrates, dedicated processing-steps are essential to upgrade the average minority charge carrier lifetime in the bulk, τbulk (Authors)