Emitters grown by rapid vapour-phase direct doping for high efficiency solar cells

In this paper we present results about excellent p-type emitters using a rapid vapour-phase direct doping (RVD) process. The main differences between the RVD process and standard BBr3 tube furnace emitters like single sided processing, short process durations and higher degree of freedom in doping profile design are discussed in detail. Lifetime samples featuring a simple RVD emitter on one side have been processed and resulted in an emitter saturation current of less than 16 fA/cm². Solar cells with the high efficiency TOPCon structure implementing this RVD emitter have been fabricated. They show open-circuit voltages of up to 687 mV, short circuit currents of up to 41.8 mA/cm², fill factors of up to 81% and a maximum efficiency of 23.3 %.