Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1513192 | Energy Procedia | 2012 | 6 Pages |
Abstract
The deposition rate of the standard (i.e. sequential) atomic layer deposition (ALD) process is very low compared to the plasma-enhanced chemical vapour deposition (PECVD) process. Therefore, as a short- and medium-term perspective, PECVD aluminium oxide (AlOx) films might be better suited for the implementation into industrial-type solar cells than ALD-Al2O3 films. In this paper, we report results achieved with a newly developed PECVD deposition process for AlOx using an inductively coupled plasma (ICP). We compare the results to high-quality ALD-Al2O3 films. We examine a stack consisting of a thin AlOx passivation layer and a PECVD silicon nitride (SiNy) capping layer. Surface recombination velocities below 9 cm/s were measured on low-resistivity (1.4 Ωcm) p-type crystalline silicon wafers passivated either by ICP-PECVD-AlOx films or by ALD-Al2O3 films after annealing at 425ÌC. Both passivation schemes provide an excellent thermal stability during firing at 910ÌC with SRVs below 12 cm/s for both, Al2O3/SiNy stacks and single Al2O3 layers. A fixed negative charge of â4Ã1012 cmâ2 is measured for ICP-AlOx and ALD-Al2O3, whereas the interface state density is higher for the ICP-AlOx layer with values of 11.0Ã1011 eVâ1cmâ2 compared to 1.3Ã1011 eVâ1cmâ2 for ALD-Al2O3. Implemented into large-area screen-printed PERC solar cells, an independently confirmed efficiency of 20.1% for ICP-AlOx and an efficiency of 19.6% for ALD-Al2O3 are achieved.
Related Topics
Physical Sciences and Engineering
Energy
Energy (General)
Authors
B. Veith, T. Dullweber, M. Siebert, C. Kranz, F. Werner, N.-P. Harder, J. Schmidt, B.F.P. Roos, T. Dippell, R. Brendel,