Boundary conditions for the industrial production of LFC cells - Results from the joint project INKA

In this paper we report about some results achieved in the joint project named INKA ("In-line Kontaktierung mittels physikalischer Gasphasen-Abscheidung" i.e. "inline contacting by gas phase deposition") conducted by Fraunhofer ISE, Deutsche Cell and Applied Material (formerly Applied Films). We evaluated the feasibility of sputtering processes for the solar cell production as well as its application for the Laser-Fired Contacts (LFC) approach. In detail we present evaluations for the rear metallisation technology feasible to deposit sufficiently thick aluminum layers. Furthermore some high efficiency solar cell results achieved during this metallisation process evaluation are presented. Finally this knowledge was applied to produce industrial-type solar cells featuring a sputtered silicon nitride rear side passivation layer as well as 2 µm of aluminum contacted by LFC with a maximum efficiency of 16.7 %.