Schematic drawing of the novel industrial POLO² IBC process sequence [12]. We apply an oxide barrier formed in the n-poly-Si anneal, a subsequent laser ablation of the oxide barrier at the p-poly edges followed by a texture etch to remove the poly-Si layers in a narrow trench region in order to insulate the n-poly-Si base contact layer from the p-poly-Si/n-poly-Si emitter tunneling contact.