Development of 4 nm-Thin PECVD aluminium oxide using plasma analysis and its application to PERC solar cells and modules

Very thin aluminum oxide passivation films (3.7 nm) are developed using ICP PECVD and applying plasma simulation (particle-in-cell Monte Carlo method), in-situ plasma characterization (spectroscopic plasma monitoring, self-excited electron plasma resonance spectroscopy, laser ellipsometry) and ex-situ layer analysis (lifetime and density of interface traps investigation). The thin (3.7 nm) AlOx films are applied to PERC-type solar cells reaching 21% efficiency slightly outperforming solar cells applying standard 15 nm AlOx layers. All solar modules manufactured applying the 3.7 nm thin AlOx passivation layer successfully passed standard damp-heat and thermal-cycling tests proving the applicability of the novel technology.