Laser processing of Al2O3/a-SiCx:H stacks: a feasible solution for the rear surface of high-efficiency p-type c-Si solar cells

Abstract

We explore the potential of laser processing aluminium oxide (Al2O3)/amorphous silicon carbide (a-SiCx:H) stacks to be used at the rear surface of p-type crystalline silicon (c-Si) solar cells. For this stack, excellent quality surface passivation is measured with effective surface recombination velocities as low as 2 cm/s. By means of an infrared laser, the dielectric film is locally opened. Simultaneously, part of the aluminium in the Al2O3 film is introduced into the c-Si, creating p+ regions that allow ohmic contacts with low-surface recombination velocities. At optimum pitch, high-efficiency solar cells are achievable for substrates of 0.5–2.5 Ω cm.