High efficiency selective emitter enabled through patterned ion implantation

Selective emitter cell architectures offer the opportunity of improved cell efficiency over standard cell architectures through improved blue response, reduced saturation current and lower contact resistance. However, few selective emitter cell concepts have been successfully adopted into high volume manufacturing, often due to the associated increase in process complexity and cost. This paper demonstrates that patterned ion implantation provides a roadmap to lower PV module and system $/Wp costs through improved cell efficiency and reduced manufacturing cost. Ion implanted cell efficiency improvements, which can be up to +1% absolute, are a result of not only the selective emitter cell architecture, but also improved emitter quality, oxide passivation and increased light collection area through the elimination of laser edge isolation. Manufacturing cost reductions result from reduced processing steps and improved process uniformity and cell binning.