A laser‐fired contact (LFC) process is one of the techniques for making local electrical contacts at the rear side of passivated emitter and rear cell (PERC) solar cells. In the LFC process, opening of the passivated dielectric layers and alloying of Si and Al need to be made in a single step laser process. For this reason, the LFC process is accompanied by the loss of Al and the laser damage to the Si wafer. In this study, we present a novel multistep LFC process combining the conventional LFC and laser‐induced forward transfer (LIFT) processes. The modified LFC scheme we proposed consists of three steps: (a) opening of the passivation layers and partial alloying of Al‐Si, (b) additional deposition of Al on the local contact holes, and (c) post laser firing of the transferred Al. Applying the modified LFC process to the PERC cells of 1.0 cm² of area, we demonstrate the effective recombination velocity of the laser‐processed wafers can be remarkably reduced while maintaining the low contact resistance. The best of the PERC solar cell fabricated by the modified LFC process exhibited an efficiency of 19.5% while the conventional LFC‐PERC cell showed 18.6%. The efficiency gains of the modified LFC‐PERC cells was largely contributed by the enhanced open circuit voltage (V_oc) and fill factor (FF).

中文翻译：

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改进的激光发射接触工艺，可实现高效的PERC太阳能电池

激光发射（LFC）工艺是在钝化发射极和后电池（PERC）太阳能电池的背面制作局部电接触的技术之一。在LFC工艺中，需要在一步激光工艺中进行钝化介电层的开放以及Si和Al的合金化。因此，LFC工艺伴随着Al的损失和激光对Si晶片的损坏。在这项研究中，我们提出了一种新颖的多步LFC工艺，将传统的LFC工艺和激光诱导的正向转移（LIFT）工艺相结合。我们提出的改进的LFC方案包括三个步骤：（a）钝化层的开放和Al-Si的部分合金化;（b）在局部接触孔上另外沉积Al;（c）激光烧制转移的铝 将修改后的LFC工艺应用于1.0 cm的PERC电池^从图2的面积可以看出，在保持较低的接触电阻的同时，可以显着降低激光加工晶片的有效复合速度。通过改进的LFC工艺制造的PERC太阳能电池中，最好的表现出19.5％的效率，而传统的LFC-PERC电池表现出18.6％的效率。改进的LFC-PERC电池的效率增益在很大程度上由增强的开路电压（V _oc）和填充系数（FF）贡献。