Laser Crystallization and Dopant Activation for a-Si:H Film in Carrier-Selective Contacts for Silicon Solar cells
George C. Wilkes1, Ajay D. Upadhyaya2, Ajeet Rohatgi2, Mool C. Gupta1
1University of Virginia, Charlottesville, VA, United States
/22Georgia Institute of Technology, Atlanta, GA, United States

Abstract  —  Herein we present a pulsed laser processing method for crystallization and dopant activation of a highly n-doped amorphous silicon (a-Si:H) carrier selective layer for high conductivity, high carrier lifetime, low emitter saturation current and limited surface layer heating as opposed to high temperature furnace annealing induced heating of the bulk Si wafer. We demonstrate increased crystallinity and reduced layer resistivity, without impacting surface passivation quality. Additionally, we examine the role of forming gas annealing (FGA) on further improving the passivation of laser-processed polysilicon layers to achieve a < 2 mΩ·cm film resistivity, 2.1 ms effective carrier lifetime, 685 mV implied open-circuit voltage (iVOC), and 27 fA/cm2recombination current density (J0) with the potential for further passivation improvement via laser process optimization.