Comparison of three different metallization concepts for LFC cells

Laser fired contacts (LFC) are a well known technique to apply the rear side electrode on dielectrically passivated solar cells. Thereby, the aluminum on top of the passivation is locally heated by means of single laser pulses and subsequently alloyed into the silicon. In this contribution we present a comparison of three different metallization procedures - physical vapor deposition (PVD), screen printing (SP) and an approach based on aluminum foil (Foil). We report about their current state regarding industrial implementation and the corresponding laser processes, as well as the complexity of these approaches. Furthermore, to compare the efficiency potential, we present results of a batch of highly efficient solar cells, featuring all approaches on an identically processed front side, leading to efficiencies of 20.9 % (PVD), 21.2 % (SP) and 21.0 % (foil).