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

• Intrinsic silicon and doped silicon oxide p-layer were optimized.
• Manufacturability of the doped silicon oxide p-layer is considered.
• Baseline data and champion solar cell data are presented.

Industry has previously established a 10% stable total module efficiency 1.1 × 1.3 m2 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 × 30 cm2 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 × 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 microcrystalline silicon oxide layer (μc-SiOx:H-p) for aluminum doped zinc oxide substrates is being presented, as well as solar cell data. The manufacturability of the μc-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.