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 J0e. For long cooling condition with proper ramping, the J0e of non-passivated p+ is at 217fA/cm2 which corresponds to an implied Voc at 669mV.