Abstract This paper reviews recent progress made at CSEM on the development of low-temperature processes for the fabrication of amorphous silicon-based passivated contacts and for the metallization of high-efficiency silicon heterojunction (SHJ) solar cells. Intrinsic a-Si:H passivation layers were optimized by trying to minimize the drop in lifetime usually observed after the deposition of the p-doped a-Si:H layer on top. State-of-the-art passivation levels are obtained, demonstrated by minority carrier lifetimes above 50 ms on lowly doped wafers, and close to 18 ms on actual SHJ cell precursors with buffer layers as thin as 4 nm. Regarding cell metallization, the screen-printing process of low-temperature Ag pastes has been optimized, resulting in finger width as low as 16 µm. Alternatively, a photolithography-free copper electroplating process has been developed. Using inkjet printing of hotmelt for patterning, 25-µm-wide and highly conductive fingers can be deposited. This process was tested in SHJ cell pilot production conditions, showing high cell performance (22.3% median efficiency) and good reproducibility. Finally, using the developed passivated contacts and screen-printing process, SHJ solar cells fabricated with industry-compatible processes showed efficiencies up to 23.1% on large-area devices and up to 23.9% on 4 cm2 devices.

中文翻译：

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高效晶体硅太阳能电池钝化和金属化的低温工艺

摘要 本文回顾了 CSEM 在非晶硅基钝化触点制造和高效硅异质结 (SHJ) 太阳能电池金属化低温工艺开发方面取得的最新进展。通过尝试将在顶部沉积 p 掺杂 a-Si:H 层后通常观察到的寿命下降最小化，优化了本征 a-Si:H 钝化层。获得了最先进的钝化水平，这证明了低掺杂晶片上的少数载流子寿命超过 50 毫秒，而缓冲层薄至 4 纳米的实际 SHJ 电池前体的寿命接近 18 毫秒。在电池金属化方面，优化了低温银浆的丝网印刷工艺，使手指宽度低至 16 µm。或者，已开发出免光刻铜电镀工艺。使用热熔胶的喷墨打印进行图案化，可以沉积 25 微米宽的高导电指状物。该工艺在 SHJ 电池中试生产条件下进行了测试，显示出高电池性能（22.3% 中值效率）和良好的重现性。最后，使用开发的钝化触点和丝网印刷工艺，采用工业兼容工艺制造的 SHJ 太阳能电池在大面积器件上显示出高达 23.1% 的效率，在 4 cm2 器件上显示出高达 23.9% 的效率。