In this study, we report on the passivation quality of atomic layer deposition grown ultra-thin Al₂O₃ and Al₂O₃ capped with plasma-enhanced chemical vapor deposition deposited SiN_x on Cz p-type wafers for the rear side of a passivated emitter and rear cell (PERC). Different activation recipes using N₂, forming gas (FG), and two-step annealing for different durations are investigated before SiN_x deposition. The effect of different Al₂O₃ thicknesses and corresponding activation processes on the Al₂O₃/SiN_x passivation performance, after a high temperature firing step, is studied to reach a new optimization toward higher efficiency and lower cost. A record high iV_oc of 720 mV is obtained after firing step from Al₂O₃/SiN_x stacks with Al₂O₃ thickness as thin as ∼2 nm with FG annealing. Our results demonstrate that, under well-optimized process conditions, ultra-thin Al₂O₃ thicknesses provide superior passivation quality as compared to the larger thicknesses which are commonly applied in the PERC industrial line and the potential for further improvement of industrial PERC solar cells in terms of cost reduction and efficiency.

中文翻译：

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用SiN封盖的超薄Al2O3使用于钝化发射极和后太阳能电池的工业p型Cz c-Si晶圆上的隐含开路电压达到720 mV

在这项研究中，我们报告了在Cz p型晶片的背面上原子生长的超薄Al ₂ O ₃和Al ₂ O _3的等离子增强钝化质量，该超薄Al ₂ O ₃和Al ₂ O ₃覆盖了等离子增强化学气相沉积SiN _x。钝化的发射极和后电池（PERC）。在SiN _x沉积之前，研究了使用N ₂，形成气体（FG）和两步退火不同持续时间的不同活化配方。不同的Al ₂ O ₃厚度和相应的活化过程对Al ₂ O ₃ / SiN _x的影响研究了高温烧制步骤后的钝化性能，以实现更高效率和更低成本的新优化。经过焙烧步骤后，通过FG退火从Al ₂ O ₃厚度薄至约2 nm的Al ₂ O ₃ / SiN _x堆中获得了720 mV的创纪录高iV _oc。我们的结果表明，在经过优化的工艺条件下，超薄Al ₂ O ₃ 与在PERC工业生产线中通常使用的较大厚度相比，该厚度提供了优异的钝化质量，并且就降低成本和效率而言，具有进一步改进工业PERC太阳能电池的潜力。