Back contact buried contact solar cells with metallization wrap around electrodes

We present results on back contact buried contact solar cells based on the Metallization Wrap Around (MWA) concept. In this cell design the current is conducted over metallized edges of the solar cell to the rear side busbar. The applied processing sequence is almost identical to the one of conventional buried contact cells and is based on p/n-contact isolation by mechanical abrasion. One major problem of MWA solar cells seems to be the long current paths in the fingers to the collecting busbar on the rear side. Therefore device simulations were carried out in order to find the optimum grid design for different cell sizes (10x10 cm(2) and 12.5x12.5 cm(2)). The device simulations showed that the MWA solar cell concept leads to higher efficiencies as compared to conventional cells. Best efficiencies obtained in this study are eta =17.5 % (cell area 25 cm(2)) and eta =16.6 % (100 cm(2)) on Cz-Si. For mc-Si efficiencies of eta =15.7 % (25 cm(2)) and eta =14.4 % (100 cm(2)) were reached.