High-rate atomic layer deposition of Al2O3 for the surface passivation of Si solar cells

Abstract

High-rate spatial atomic layer deposition (ALD) enables an industrially relevant deposition of high-quality aluminum oxide (Al2O3) films for the surface passivation of silicon solar cells. We demonstrate a homogeneous surface passivation at a deposition rate of ∼30 nm/min on 15.6×15.6 cm2 silicon wafers of 10 nm thick Al 2O3 layers deposited in a novel inline spatial ALD system. The effective surface recombination velocity on n-type Czochralski-grown (Cz) silicon wafers is shown to be virtually independent of injection level. Surface recombination velocities below 2.9 cm/s and an extremely low interface state density below 8×1010 eV-1cm-2 are achieved. We demonstrate that the novel inline spatial ALD system provides the means to integrate Al2O3 passivation layers into industrial solar cells.