Influence of precursor gas ratio and firing on silicon surface passivation by APCVD aluminium oxide

Using a high throughput, in-line atmosphere chemical vapor deposition (APCVD) tool, we have synthesized amorphous aluminum oxide (AlOx) films from precursors of trimethyl-aluminum (TMA) and O-2, yielding a maximum deposition 150 nm min(-1) per wafer. For p-type crystalline silicon (c-Si) wafers, excellent surface passivation was achieved with the APCVD AlOx films, with a best maximum effective surface recombination velocity (S-eff,S-max) of 8 cm/s following a standard industrial firing step. The findings could be attributed to the existence of large negative charge (Q(f) approximate to -3 x 10(12) cm(-2)) and low interface defect density (D-it approximate to 4 x 10(11) eV(-1) cm(-2)) achieved by the films. This data demonstrates a high potential for APCVD AlOx to be used in high efficiency, low cost industrial solar cells. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)