Plasma enhanced chemical vapor deposition process optimization for thin film silicon tandem junction solar cells

Industry has previously established a 10% stable total module efficiency 1.1 x 1.3 m(2) thin film silicon tandem junction (TJ) module manufacturing baseline. A similar silicon TJ cell manufacturing process has been established, using a plasma enhanced chemical vapor deposition (PECVD) tool with an excitation frequency of 13.56 MHz, which was modified to handle 30 x 30 cm(2) substrates. Extensive PECVD process window characterization was undertaken for the silicon layers that have the biggest impact on device performance. Single layer silicon on glass data and 1 x 1 cm2 single junction and TJ solar cell data for amorphous intrinsic silicon and microcrystalline intrinsic silicon layers have been collected. Single layer characterization data for p-doped micro-crystalline silicon oxide layer (mu c-SiOx:H-p) for aluminum doped zinc oxide substrates is being presented, as well as solar cell data. The manufacturability of the mu c-SiOx:H-p process is being considered. Finally, we present the best solar cell results obtained with the optimized PECVD process, as well as baseline performance data. (C) 2014 Elsevier B. V. All rights reserved.