Optimization of the rear contact pattern of high‐efficiency silicon solar cells with and without local back surface field

The influence of the point spacing and size on the cell efficiency is studied for different silicon solar cell structures with local rear contacts: the PERC (passivated emitter and rear cell) with its high recombination at the rear contacts and the LBSF (local back surface field) or PERL (passivated emitter and rear locally diffused) cell with reduced combination at the rear contacts due to a diffused high‐low junction (or LBSF) beneath the contacts. Float zone materials of different resistivities have been investigated. The experimental results are explained by three‐dimensional finite difference simulations for the open‐circuit voltage, the short‐circuit current and the fill factor.