Investigation of cooling effect on alloying Al-p+ emitter for n-type silicon solar cell

In this study, we demonstrate a concept for optimizing the alloying process for Al-p+ emitter formation with a commercially available aluminum paste, screen-printing technology and belt-conveyor furnace. A more uniform and conformal Al-p+ emitter is obtained at the sample with slow cooling condition of alloying process. Among the 8μm-thick emitters formed by various alloying profiles, the result shows the condition with moderate cooling rate leads to lower J_0e. For long cooling condition with proper ramping, the J_0e of non-passivated p+ is at 217fA/cm² which corresponds to an implied Voc at 669mV.