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In this study, a self-developed atmospheric pressure atomic layer deposition (APALD) system is used to deposit Al2O3 passivation film, along with the use of precursor combinations of Al(CH3)3/H2O to improve its passivation characteristics through a short-time microwave post-annealing process. Comparing the unannealed and microwave-annealed samples whose temperature is controlled at 200–500 °C, APALD non-vacuum deposited film can be realized with a higher film deposition rate, which is beneficial for increasing the production throughput while at the same time reducing the operating cost of vacuum equipment at hand. Since the microwave has a greater penetration depth during the process, the resultant thermal energy provided can be spread out evenly to the entire wafer, thereby achieving the effect of rapid annealing. The film thickness is subsequently analyzed by TEM, whereas the chemical composition is verified by EDS and XPS. The negative fixed charge and interface trap density are analyzed by the C-V measurement method. Finally, the three major indicators of τeff, SRV, and IVoc are analyzed by QSSPC to duly verify the excellent passivation performance. [ABSTRACT FROM AUTHOR]

In this study, Atomic Layer Deposition (ALD) equipment was used to deposit Al2O3 film on a p-type silicon wafer, trimethylaluminum (TMA) and H2O were used as precursor materials, and then the post-annealing process was conducted under atmospheric pressure. The Al2O3 films annealed at different temperatures between 200–500 °C were compared to ascertain the effect of passivation films and to confirm the changes in film structure and thickness before and after annealing through TEM images. Furthermore, the negative fixed charge and interface defect density were analyzed using the C-V measurement method. Photo-induced carrier generation was used to measure the effective minority carrier lifetime, the implied open-circuit voltage, and the effective surface recombination velocity of the film. The carrier lifetime was found to be the longest (2181.7 μs) for Al2O3/Si post-annealed at 400 °C. Finally, with the use of VHF (40.68 MHz) plasma-enhanced chemical vapor deposition (PECVD) equipment, a silicon nitride (SiNx) film was plated as an anti-reflection layer over the front side of the wafer and as a capping layer on the back to realize a passivated emitter and rear contact (PERC) solar cell with optimal efficiency up to 21.54%. [ABSTRACT FROM AUTHOR]